Docs: fix and standardize Maple and RET6 hardware pages.

Pick a standard layout for the information and fix mistakes.  Looks
like some of these errors were copy-pasted in from the old HTML
documentation, some crept in due to API changes, and some were just
wrong.

I've checked all the claims against the datasheets and source code, so
we should be in good shape now.

2 files changed, 372 insertions, 266 deletions

diff --git a/source/hardware/maple-ret6.rst b/source/hardware/maple-ret6.rst
index 9ee46d2..2f636d7 100644
--- a/source/hardware/maple-ret6.rst
+++ b/source/hardware/maple-ret6.rst
@@ -5,56 +5,60 @@
 Maple RET6 Edition
 ==================
 
+This page is a general resource for information specific to the Maple
+RET6 Edition.  The Maple RET6 Edition is a "beta" board released as a
+simple way to get a more powerful chip than the one on the base Maple
+(the STM32F103RET6, hence the name) in the hands of Maple developers.
+
 .. contents:: Contents
    :local:
 
+.. TODO [dma.rst] Ref to dma.rst in sequel instead of libmaple-dma
+.. TODO [dac.rst] Ref to dac.rst in sequel instead of libmaple-dac
+.. TODO [nvic.rst] Ref to nvic.rst in sequel
+
 Technical Specifications
 ------------------------
 
-    * MCU: **STM32F103RET6**, a 32-bit ARM Cortex M3 microprocessor
-    * Clock Speed: **72 MHz**
-    * **512KB Flash** and **64KB SRAM**
-    * 43 Digital I/O Pins (:ref:`GPIO <gpio>`)
-    * 16 Analog Input pins, 12 bit **ADC** resolution (:ref:`ADC
-      <adc>`)
-    * Built-in, 2 channel **DAC** at 12 bit resolution
-      (:ref:`libmaple-dac`).
-    * 19 **PWM** pins at 16-bit resolution (:ref:`PWM <pwm>`)
-    * Dedicated **USB** port for programming and communications
-      (:ref:`USB<usb>`)
-    * External **JTAG** interface (:ref:`JTAG <jtag>`)
-    * 64 Channel nested vector interrupt handler (including
-      :ref:`external interrupt <lang-attachinterrupt>` on GPIOs)
-    * Integrated **SPI** (:ref:`SPI <spi>`)
-    * Integrated **SDIO**
-    * Integrated **I2C** and **I2S** (:ref:`I2C <i2c>`)
-    * 12 Channels of Direct Memory Access (**DMA**)
-      (:ref:`libmaple-dma`)
-    * 3 **USART** and 2 **UART** devices (:ref:`USART <usart>`)
-    * Two advanced control, four general purpose, two basic **timers**
-      (:ref:`timers`)
-    * Supplies up to 500mA @ 3.3v (with separate 250 mA digital and
-      analog regulators)
-    * Support for low power, sleep, and standby modes (<500uA)
-    * Operating Voltage: 3.3V
-    * Input Voltage (recommended): 3V-12V
-    * Dimensions are 2.05″x2.1″
+* MCU: **STM32F103RET6**, a 32-bit ARM Cortex M3 microprocessor
+* Clock Speed: **72 MHz**
+* **512 KB Flash** and **64 KB SRAM**
+* 43 Digital I/O Pins (:ref:`gpio`)
+* 18 **PWM** pins at 16 bit resolution (:ref:`pwm`)
+* 15 analog input pins, 12 bit **ADC** resolution (:ref:`adc`)
+* Built-in, 2 channel **DAC** at 12 bit resolution (:ref:`libmaple-dac`).
+* 2 **SPI** peripherals with **I2S** support (:ref:`spi`)
+* 2 **I2C** peripherals (:ref:`i2c`)
+* 12 Channels of Direct Memory Access (**DMA**)
+  (:ref:`libmaple-dma`) with 2 DMA controllers
+* 3 **USART** devices (:ref:`usart`)
+* 2 advanced, 4 general-purpose, and 2 basic **timers** (:ref:`timers`)
+* Dedicated **USB** port for programming and communications (:ref:`usb`)
+* **JTAG** (:ref:`jtag`)
+* Nested Vectored Interrupt Controller (NVIC) (including
+  :ref:`external interrupt <lang-attachinterrupt>` on GPIOs)
+* Supplies up to 500 mA at 3.3 V, with :ref:`separate 250 mA digital
+  and analog regulators <maple-ret6-adc-bank>` for low-noise analog
+  performance
+* :ref:`Four layer design <maple-ret6-hardware>`
+* Support for low power, sleep, and standby modes (<500 μA)
+* Operating Voltage: 3.3 V
+* Input Voltage (recommended): 4 V — 12 V
+* Dimensions are 2.05″ × 2.1″
 
 .. _maple-ret6-powering:
 
 Powering the Maple RET6 Edition
 -------------------------------
 
-The Maple RET6 Edition's power source is determined by the header to
-the left of the "LeafLabs" label on the silkscreen.  The RET6 Edition
-can be powered from the barrel jack connector, USB, or a LiPo battery.
-We ship the RET6 Edition with a jumper on the USB selector.  In order
-to power it off of an alternative source, unplug the board, then move
-the jumper to the desired selector before reconnecting power.
+The Maple RET6 Edition is powered in the :ref:`same way as the
+standard Maple <maple-powering>`.
 
-You can also power the Maple via the pin labeled "Vin" on the lower
-header.  However, don't do this while simultaneously powering the
-board from another source, or you could damage the board.
+.. warning:: The RET6 Edition silkscreen falsely indicates that the
+   barrel jack accepts up to 18 V.  We recommend a barrel jack input
+   voltage **no greater than 12 V**.
+
+   See :ref:`this erratum <maple-barrel-jack>` for more information.
 
 Using the Built-in Battery Charger
 ----------------------------------
@@ -84,7 +88,8 @@ It is thus mainly useful as an :ref:`input <lang-pin-levels>`.  The
 pin will :ref:`read <lang-digitalread>` ``HIGH`` when the :ref:`button
 is pressed <lang-isbuttonpressed>`.
 
-More GPIOs (numbered ``D39``\ --``D42``) are available if you use the
+More GPIOs (numbered ``D39``\ --``D42`` on the back of the RET6
+Edition's silkscreen) are available if you use the
 :ref:`lang-disabledebugports` function; see the :ref:`board-specific
 debug pin constants <lang-board-values-debug>` for more information.
 (See :ref:`this erratum <maple-ret6-nrst-pb4>` for information about
@@ -97,57 +102,58 @@ the pin numbered ``43`` on the silkscreen).
 Master Pin Map
 ^^^^^^^^^^^^^^
 
-This table shows the available functionality on every GPIO pin, by
-peripheral type. The "STM32" column refers to the port and number that
-the header is connected to on the microcontroller.  The "5V?" column
-documents whether or not the pin is 5 volt tolerant.
+This table shows a summary of the available functionality on every
+GPIO pin, by peripheral type.  The "5 V?" column documents whether or
+not the pin is 5 volt tolerant.
 
 .. csv-table::
-   :header: Pin, STM32, :ref:`ADC <adc>`, :ref:`Timer <timers>`, :ref:`I2C <i2c>`, :ref:`UART <usart>`, :ref:`SPI <spi>`, 5v?
-
-   D0,  PA3,  ADC3,  TIM2_CH4,     -,          USART2_RX,  -,         -
-   D1,  PA2,  ADC2,  TIM2_CH3,     -,          USART2_TX,  -,         -
-   D2,  PA0,  ADC0,  TIM2_CH1_ETR, -,          USART2_CTS, -,         -
-   D3,  PA1,  ADC1,  TIM2_CH2,     -,          USART2_RTS, -,         -
-   D4,  PB5,  -,     -,            ISC1_SMBA,  -,          SPI3_MOSI, -
-   D5,  PB6,  -,     TIM4_CH1,     I2C1_SCL,   -,          -,         Yes
-   D6,  PA8,  -,     TIM1_CH1,     -,          USART1_CK,  -,         Yes
-   D7,  PA9,  -,     TIM1_CH2,     -,          USART1_TX,  -,         Yes
-   D8,  PA10, -,     TIM1_CH3,     -,          USART1_RX,  -,         Yes
-   D9,  PB7,  -,     TIM4_CH2,     I2C1_SDA,   -,          -,         Yes
-   D10, PA4,  ADC4,  -,            -,          USART2_CK,  SPI1_NSS,  -
-   D11, PA7,  ADC7,  TIM3_CH2,     -,          -,          SPI1_MOSI, -
-   D12, PA6,  ADC6,  TIM3_CH1,     -,          -,          SPI1_MISO, -
-   D13, PA5,  ADC5,  -,            -,          -,          SPI1_SCK,  -
-   D14, PB8,  -,     TIM4_CH3,     -,          -,          -,         Yes
-   D15, PC0,  ADC10, -,            -,          -,          -,         -
-   D16, PC1,  ADC11, -,            -,          -,          -,         -
-   D17, PC2,  ADC12, -,            -,          -,          -,         -
-   D18, PC3,  ADC13, -,            -,          -,          -,         -
-   D19, PC4,  ADC14, -,            -,          -,          -,         -
-   D20, PC5,  ADC15, -,            -,          -,          -,         -
-   D21, PC13, -,     -,            -,          -,          -,         -
-   D22, PC14, -,     -,            -,          -,          -,         -
-   D23, PC15, -,     -,            -,          -,          -,         -
-   D24, PB9,  -,     TIM4_CH4,     -,          -,          -,         Yes
-   D25, PD2,  -,     TIM3_ETR,     -,          -,          UART5_RX,  Yes
-   D26, PC10, -,     -,            -,          -,          UART4_TX,  Yes
-   D27, PB0,  ADC8,  TIM3_CH3,     -,          -,          -,         -
-   D28, PB1,  ADC9,  TIM3_CH4,     -,          -,          -,         -
-   D29, PB10, -,     -,            I2C2_SCL,   USART3_TX,  -,         Yes
-   D30, PB11, -,     -,            I2C2_SDA,   USART3_RX,  -,         Yes
-   D31, PB12, -,     TIM1_BKIN,    I2C2_SMBA,  USART3_CK,  SPI2_NSS,  Yes
-   D32, PB13, -,     TIM1_CH1N,    -,          USART3_CTS, SPI2_SCK,  Yes
-   D33, PB14, -,     TIM1_CH2N,    -,          USART3_RTS, SPI2_MISO, Yes
-   D34, PB15, -,     TIM1_CH3N,    -,          -,          SPI2_MOSI, Yes
-   D35, PC6,  -,     TIM8_CH1,     -,          -,          -,         Yes
-   D36, PC7,  -,     TIM8_CH2,     -,          -,          -,         Yes
-   D37, PC8,  -,     TIM8_CH3,     -,          -,          -,         Yes
-   D38, PC9,  -,     TIM8_CH4,     -,          -,          -,         Yes
-   D39, PA13, -,     -,            -,          -,          -,         Yes
-   D40, PA14, -,     -,            -,          -,          -,         Yes
-   D41, PA15, -,     -,            -,          -,          SPI3_NSS,  Yes
-   D42, PB3,  -,     -,            -,          -,          SPI3_SCK,  Yes
+   :header: Pin, :ref:`GPIO <gpio>`, :ref:`ADC <adc>`, :ref:`Timer <timers>`, :ref:`I2C <i2c>`, :ref:`UART/USART <usart>`, :ref:`SPI <spi>`, 5 V?
+
+   D0,  PA3,  CH3,  2_CH4,     -,       2_RX,  -,      -
+   D1,  PA2,  CH2,  2_CH3,     -,       2_TX,  -,      -
+   D2,  PA0,  CH0,  2_CH1_ETR, -,       2_CTS, -,      -
+   D3,  PA1,  CH1,  2_CH2,     -,       2_RTS, -,      -
+   D4,  PB5,  -,    -,         1_SMBA,  -,     3_MOSI, -
+   D5,  PB6,  -,    4_CH1,     1_SCL,   -,     -,      Yes
+   D6,  PA8,  -,    1_CH1,     -,       1_CK,  -,      Yes
+   D7,  PA9,  -,    1_CH2,     -,       1_TX,  -,      Yes
+   D8,  PA10, -,    1_CH3,     -,       1_RX,  -,      Yes
+   D9,  PB7,  -,    4_CH2,     1_SDA,   -,     -,      Yes
+   D10, PA4,  CH4,  -,         -,       2_CK,  1_NSS,  -
+   D11, PA7,  CH7,  3_CH2,     -,       -,     1_MOSI, -
+   D12, PA6,  CH6,  3_CH1,     -,       -,     1_MISO, -
+   D13, PA5,  CH5,  -,         -,       -,     1_SCK,  -
+   D14, PB8,  -,    4_CH3,     -,       -,     -,      Yes
+   D15, PC0,  CH10, -,         -,       -,     -,      -
+   D16, PC1,  CH11, -,         -,       -,     -,      -
+   D17, PC2,  CH12, -,         -,       -,     -,      -
+   D18, PC3,  CH13, -,         -,       -,     -,      -
+   D19, PC4,  CH14, -,         -,       -,     -,      -
+   D20, PC5,  CH15, -,         -,       -,     -,      -
+   D21, PC13, -,    -,         -,       -,     -,      -
+   D22, PC14, -,    -,         -,       -,     -,      -
+   D23, PC15, -,    -,         -,       -,     -,      -
+   D24, PB9,  -,    4_CH4,     -,       -,     -,      Yes
+   D25, PD2,  -,    3_ETR,     -,       -,     5_RX,   Yes
+   D26, PC10, -,    -,         -,       -,     4_TX,   Yes
+   D27, PB0,  CH8,  3_CH3,     -,       -,     -,      -
+   D28, PB1,  CH9,  3_CH4,     -,       -,     -,      -
+   D29, PB10, -,    -,         2_SCL,   3_TX,  -,      Yes
+   D30, PB11, -,    -,         2_SDA,   3_RX,  -,      Yes
+   D31, PB12, -,    1_BKIN,    2_SMBA,  3_CK,  2_NSS,  Yes
+   D32, PB13, -,    1_CH1N,    -,       3_CTS, 2_SCK,  Yes
+   D33, PB14, -,    1_CH2N,    -,       3_RTS, 2_MISO, Yes
+   D34, PB15, -,    1_CH3N,    -,       -,     2_MOSI, Yes
+   D35, PC6,  -,    8_CH1,     -,       -,     -,      Yes
+   D36, PC7,  -,    8_CH2,     -,       -,     -,      Yes
+   D37, PC8,  -,    8_CH3,     -,       -,     -,      Yes
+   D38, PC9,  -,    8_CH4,     -,       -,     -,      Yes
+   D39, PA13, -,    -,         -,       -,     -,      Yes
+   D40, PA14, -,    -,         -,       -,     -,      Yes
+   D41, PA15, -,    -,         -,       -,     3_NSS,  Yes
+   D42, PB3,  -,    -,         -,       -,     3_SCK,  Yes
+
+.. _maple-ret6-timer-map:
 
 Timer Pin Map
 ^^^^^^^^^^^^^
@@ -188,7 +194,7 @@ The following table shows which pins connect to which :ref:`EXTI lines
    * - EXTI2
      - 1, 17, 25
    * - EXTI3
-     - 0, 18
+     - 0, 18, 42
    * - EXTI4
      - 10, 19
    * - EXTI5
@@ -208,11 +214,11 @@ The following table shows which pins connect to which :ref:`EXTI lines
    * - EXTI12
      - 31
    * - EXTI13
-     - 21, 32
+     - 21, 32, 39
    * - EXTI14
-     - 22, 33
+     - 22, 33, 40
    * - EXTI15
-     - 23, 34
+     - 23, 34, 41
 
 .. _maple-ret6-usart-map:
 
@@ -220,9 +226,8 @@ USART Pin Map
 ^^^^^^^^^^^^^
 
 The Maple RET6 Edition has three serial ports whose pins are broken
-out to headers (also known as a UARTs or USARTs): ``Serial1``,
-``Serial2``, and ``Serial3``. They communicate using the pins
-summarized in the following table:
+out to headers (also known as :ref:`USARTs <usart>`). They communicate
+using the pins summarized in the following table:
 
 .. csv-table::
    :header: Serial Port, TX, RX, CK, CTS, RTS
@@ -233,7 +238,18 @@ summarized in the following table:
    ``Serial3`` | 29 | 30 | 31 | 32 | 33
 
 Unfortunately, :ref:`UART4 and UART5 aren't completely available
-<maple-ret6-uart-errata>`.
+<maple-ret6-uarts>`.
+
+.. _maple-ret6-adc-bank:
+
+Low-Noise ADC Pins
+^^^^^^^^^^^^^^^^^^
+
+The six pins at the bottom right of the board (D15—D20) generally
+offer lower-noise ADC performance than other pins on the board. If
+you’re concerned about getting good ADC readings, we recommend using
+one of these pins to take your measurements.  More details in the
+:ref:`Maple hardware documentation <maple-adc-bank>`.
 
 Board-Specific Values
 ---------------------
@@ -244,24 +260,28 @@ values <lang-board-values>`.
 - ``CYCLES_PER_MICROSECOND``: 72
 - ``BOARD_BUTTON_PIN``: 38
 - ``BOARD_LED_PIN``: 13
-- ``BOARD_NR_GPIO_PINS``: 44
-- ``BOARD_NR_PWM_PINS``: 16
-- ``boardPWMPins``: 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 14, 24, 25, 27, 28
+- ``BOARD_NR_GPIO_PINS``: 44 (however, :ref:`pin D43 is not usable
+  <maple-nrst-pb4>`)
+- ``BOARD_NR_PWM_PINS``: 18
+- ``boardPWMPins``: 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 14, 24, 27, 28,
+  35, 36, 37
 - ``BOARD_NR_ADC_PINS``: 15
-- ``boardADCPins``: 0, 1, 2, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 27, 28
+- ``boardADCPins``: 0, 1, 2, 3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 27, 28
 - ``BOARD_NR_USED_PINS``: 7
 - ``boardUsedPins``: ``BOARD_LED_PIN``, ``BOARD_BUTTON_PIN``,
   ``BOARD_JTMS_SWDIO_PIN``, ``BOARD_JTCK_SWCLK_PIN``,
   ``BOARD_JTDI_PIN``, ``BOARD_JTDO_PIN``, ``BOARD_NJTRST_PIN``
-- ``BOARD_NR_USARTS``: 3 (unfortunately, due to the Maple Rev 5
-  design, UARTs 4 and 5 have pins which are not broken out)
+- ``BOARD_NR_USARTS``: 3 (unfortunately, :ref:`due to the Maple Rev 5
+  design <maple-ret6-uarts>`, UARTs 4 and 5 have pins which are not
+  broken out).
 - ``BOARD_USART1_TX_PIN``: 7
 - ``BOARD_USART1_RX_PIN``: 8
 - ``BOARD_USART2_TX_PIN``: 1
 - ``BOARD_USART2_RX_PIN``: 0
 - ``BOARD_USART3_TX_PIN``: 29
 - ``BOARD_USART3_RX_PIN``: 30
-- ``BOARD_NR_SPI``: 3
+- ``BOARD_NR_SPI``: 2 (unfortunately, :ref:`due to the Maple Rev 5
+  design <maple-ret6-nrst-pb4>`, SPI3 is unavailable).
 - ``BOARD_SPI1_NSS_PIN``: 10
 - ``BOARD_SPI1_MOSI_PIN``: 11
 - ``BOARD_SPI1_MISO_PIN``: 12
@@ -270,21 +290,19 @@ values <lang-board-values>`.
 - ``BOARD_SPI2_MOSI_PIN``: 34
 - ``BOARD_SPI2_MISO_PIN``: 33
 - ``BOARD_SPI2_SCK_PIN``: 32
-- ``BOARD_SPI3_NSS_PIN``: 41
-- ``BOARD_SPI3_MOSI_PIN``: 4
-- ``BOARD_SPI3_MISO_PIN``: 43
-- ``BOARD_SPI3_SCK_PIN``: 42
 - ``BOARD_JTMS_SWDIO_PIN``: 39
 - ``BOARD_JTCK_SWCLK_PIN``: 40
 - ``BOARD_JTDI_PIN``: 41
 - ``BOARD_JTDO_PIN``: 42
-- ``BOARD_NJTRST_PIN``: 43
+- ``BOARD_NJTRST_PIN``: :ref:`43 <maple-ret6-nrst-pb4>`
+
+.. _maple-ret6-hardware:
 
 Hardware Design Files
 ---------------------
 
 The hardware schematics and board layout files are available in the
-`Maple Github repository <https://github.com/leaflabs/maple>`_.  Other
+`Maple GitHub repository <https://github.com/leaflabs/maple>`_.  Other
 than the processor used, the design files for the Maple RET6 edition
 are identical to the Maple Rev 5, which are in the ``maple-r5``
 subdirectory of the Maple repository.  A schematic for a JTAG adapter
@@ -293,7 +311,7 @@ directory.
 
 From the GitHub repository main page, you can download the entire
 repository by clicking the "Download" button.  If you are familiar
-with `git <http://git-scm.com/>`_, you can also clone the repository
+with `Git <http://git-scm.com/>`_, you can also clone the repository
 at the command line with ::
 
     $ git clone git://github.com/leaflabs/maple.git
@@ -315,48 +333,81 @@ damage your board permanently.
 Errata
 ------
 
-This section lists known issues and warnings for the Maple RET6 Edition.
+This section lists known issues and warnings for the Maple RET6
+Edition.  Some of these are simply due to the RET6 Edition using the
+Maple's circuit board, which was not designed to accomodate extra
+features only available on the STM32F103RET6.
 
-* **Power Supply Marketing Mistake**: We originally sold the Maple
+.. _maple-ret6-barrel-jack:
+
+* **Barrel jack power supply voltage mistake**: The silkscreen next to
+  the barrel jack connector incorrectly indicates that up to an 18 V
+  input voltage is allowed.  **We do not recommend exceeding 12 V**.
+
+  See this :ref:`Maple erratum <maple-barrel-jack>` for more
+  information.
+
+* **Power supply marketing mistake**: We originally sold the Maple
   RET6 Edition advertising that it was capable of supplying up to 800
   mA; the correct value is 500 mA.
 
-.. _maple-ret6-uart-errata:
+.. _maple-ret6-uarts:
 
 * **UART4, UART5 GPIOs unavailable**: Pins related to UARTs 4 and 5
   are not broken out to headers (specifically, PC11/UART4_RX and
-  PC12/UART5_TX).  The RET6 Edition's hardware layout is identical to
-  that of the Maple Rev 5, which wasn't designed for use with these
-  STM32F103RET6-only peripherals.
+  PC12/UART5_TX).  This is due to the RET6 Edition's board layout
+  being that of the Maple Rev 5, which was not designed with these
+  RET6-specific features in mind.
 
 .. _maple-ret6-dac-ch2:
 
 * **DAC channel 2 on BOARD_LED_PIN**: The Maple Rev 5 connects PA5 to
   the board's built-in LED; this is the same GPIO bit which is
   connected to the DAC's channel 2 output.  This is also due to the
-  RET6 Edition's board layout being copied from the base Maple Rev 5.
+  RET6 Edition's board layout being that of the Maple Rev 5.  The DAC
+  output channel is still available, and (if you use libmaple) its
+  output is buffered by default, so this may not significantly
+  interfere with its functionality.
 
 .. _maple-ret6-nrst-pb4:
 
 * **Reset and PB4 tied together**: The RET6 Edition's reset line is
   also connected to PB4, which is labeled on the silkscreen as pin 43.
-  Thus, attempting to use pin 43 as a GPIO may reset your board.  This
+  Thus, attempting to use pin 43 as a GPIO can reset your board.  This
   has other implications.  Since PB4 is also the JTAG NJTRST line,
   this prevents the :ref:`JTAG <jtag>` "reset halt" command from
   working properly.  Also, since PB4 is SPI3_MISO, the SPI3 peripheral
   is not fully usable.
 
+.. _maple-ret6-sdio:
+
+* **SDIO lines not broken out**: The RET6 Edition's SDIO peripheral is
+  not usable, as some of its data lines are either not broken out or
+  used for other purposes.  This is also due to the RET6 Edition's
+  board layout being that of the Maple Rev 5.
+
+.. _maple-ret6-adc-led:
+
+* **ADC on BOARD_LED_PIN**: We originally sold the Maple RET6 Edition
+  advertising 16 analog input lines.  However, one of them (the one on
+  pin 13) is also connected to the built-in LED.  The voltage drop
+  across the LED means that the analog to digital converter on that
+  pin is not really useful.  While it is still usable, its readings
+  will be incorrect.
+
 Recommended Reading
 -------------------
 
-* STMicro documentation for STM32F103RE microcontroller:
-
-    * `Datasheet
-      <http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00191185.pdf>`_ (PDF)
-    * `Reference Manual
-      <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (PDF)
-    * `Programming Manual
-      <http://www.st.com/stonline/products/literature/pm/15491.pdf>`_
-      (PDF; assembly language and register reference)
-    * `ST's STM32F103RE reference page
-      <http://www.st.com/internet/mcu/product/164485.jsp>`_
+STMicro documentation for STM32F103RE microcontroller:
+
+* `Datasheet
+  <http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00191185.pdf>`_
+  (PDF); covers STM32F103xC, STM32F103xD, STM32F103xE.
+* `Reference Manual RM0008
+  <http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/REFERENCE_MANUAL/CD00171190.pdf>`_
+  (PDF); general, definitive resource for STM32F1 line.
+* `Programming Manual PM0056
+  <http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/PROGRAMMING_MANUAL/CD00228163.pdf>`_
+  (PDF); assembly language and register reference.
+* `STM32F103RE <http://www.st.com/internet/mcu/product/164485.jsp>`_
+  overview page with links to further references.
diff --git a/source/hardware/maple.rst b/source/hardware/maple.rst
index bb4bf35..b6950e0 100644
--- a/source/hardware/maple.rst
+++ b/source/hardware/maple.rst
@@ -5,36 +5,39 @@
 Maple
 =====
 
+This page is a general resource for information specific to the Maple.
+
 .. contents:: Contents
    :local:
 
+.. TODO [dma.rst] Ref to dma.rst in sequel instead of libmaple-dma
+.. TODO [nvic.rst] Ref to nvic.rst in sequel
+
 Technical Specifications
 ------------------------
 
-    * MCU: **STM32F103RBT6**, a 32-bit ARM Cortex M3 microprocessor
-    * Clock Speed: **72 MHz**
-    * **128KB Flash** and **20KB SRAM**
-    * 43 Digital I/O Pins (:ref:`GPIO <gpio>`)
-    * 16 Analog Input Pins, 12-bit **ADC** resolution (:ref:`ADC
-      <adc>`)
-    * 15 **PWM** pins at 16-bit resolution (:ref:`PWM <pwm>`)
-    * Dedicated **USB** port for programming and communications
-      (:ref:`USB <usb>`)
-    * External **JTAG** interface (:ref:`JTAG <jtag>`)
-    * 64 Channel nested vector interrupt handler (including
-      :ref:`external interrupt <lang-attachinterrupt>` on GPIOs)
-    * Integrated **SPI** (:ref:`SPI <spi>`)
-    * Integrated **I2C** (:ref:`I2C <i2c>`)
-    * 7 Channels of Direct Memory Access (**DMA**)
-      (:ref:`libmaple-dma`)
-    * 3 **USART** divices (:ref:`USART <usart>`)
-    * Four 4-channel **timers** (:ref:`Timers <timers>`)
-    * Supplies up to 500mA @ 3.3v (with separate 250 mA digital and
-      analog regulators)
-    * Support for low power, sleep, and standby modes (<500uA)
-    * Operating Voltage: 3.3V
-    * Input Voltage (recommended): 3V-12V
-    * Dimensions are 2.05″x2.1″
+* MCU: **STM32F103RBT6**, a 32-bit ARM Cortex M3 microprocessor
+* Clock Speed: **72 MHz**
+* **128 KB Flash** and **20 KB SRAM**
+* 43 Digital I/O Pins (:ref:`gpio`)
+* 15 **PWM** pins at 16 bit resolution (:ref:`pwm`)
+* 15 analog input pins, 12-bit **ADC** resolution (:ref:`adc`)
+* 2 **SPI** peripherals (:ref:`spi`)
+* 2 **I2C** peripherals (:ref:`i2c`)
+* 7 Channels of Direct Memory Access (**DMA**) (:ref:`libmaple-dma`)
+* 3 **USART** peripherals (:ref:`usart`)
+* One advanced and three general-purpose **timers** (:ref:`timers`)
+* Dedicated **USB** port for programming and communications (:ref:`usb`)
+* **JTAG** (:ref:`jtag`)
+* Nested Vectored Interrupt Controller (NVIC) (including
+  :ref:`external interrupt <external-interrupts>` on GPIOs)
+* Supplies up to 500 mA at 3.3 V, with separate 250 mA digital and
+  analog regulators for low-noise analog performance
+* :ref:`Four layer design <maple-hardware>`
+* Support for low power, sleep, and standby modes (<500 μA)
+* Operating Voltage: 3.3 V
+* Input Voltage (recommended): 4 V — 12 V
+* Dimensions: 2.05″ × 2.1″
 
 .. _maple-identify-rev:
 
@@ -49,7 +52,7 @@ Rev.
 Rev 5
 ^^^^^
 
-These boards went on sale in November 2010.  They have white buttons,
+These boards went on sale in November 2010.  They have white buttons
 and "r5" in small print near the "LeafLabs Maple" text next to the
 "infinity leaf" logo.  The Maple Rev 5 repositioned the double header
 on the right hand side to better fit 0.1 inch pitch breadboard.  This
@@ -96,8 +99,16 @@ it off of an alternative source, unplug the Maple, then move the
 jumper to the desired selector before reconnecting power.
 
 You can also power the Maple via the pin labeled "Vin" on the lower
-header.  However, don't do this while simultaneously powering the
-Maple from another source, or you could damage the board.
+header.  This pin feeds into both the digital and analog voltage
+regulators.  However, don't do this while simultaneously powering the
+board from another source, or you could damage it.
+
+.. warning:: Silkscreens on Maples up through Rev 5s manufactured in
+   Spring 2011 falsely indicated that the barrel jack could be
+   supplied by up to 18 V.  We recommend a barrel jack input voltage
+   **no greater than 12 V**.
+
+   See :ref:`this erratum <maple-barrel-jack>` for more information.
 
 Using the Built-in Battery Charger
 ----------------------------------
@@ -127,11 +138,12 @@ It is thus mainly useful as an :ref:`input <lang-pin-levels>`.  The
 pin will :ref:`read <lang-digitalread>` ``HIGH`` when the :ref:`button
 is pressed <lang-isbuttonpressed>`.
 
-More GPIOs (numbered ``D39``\ --``D42``) are available if you use the
-:ref:`lang-disabledebugports` function; see the :ref:`board-specific
-debug pin constants <lang-board-values-debug>` for more information.
-(See :ref:`this erratum <maple-nrst-pb4>` for information about the
-pin numbered ``43`` on the silkscreen).
+More GPIOs (numbered ``D39``\ --``D42`` on the back of the Maple's
+silkscreen) are available if you use the :ref:`lang-disabledebugports`
+function; see the :ref:`board-specific debug pin constants
+<lang-board-values-debug>` for more information.  (See :ref:`this
+erratum <maple-nrst-pb4>` for information about the pin numbered
+``43`` on the silkscreen).
 
 .. TODO [0.1.0] silkscreen pictures which expand abbreviations
 
@@ -140,57 +152,58 @@ pin numbered ``43`` on the silkscreen).
 Master Pin Map
 ^^^^^^^^^^^^^^
 
-This table shows the available functionality on every GPIO pin, by
-peripheral type. The "STM32" column refers to the port and number that
-the header is connected to on the microcontroller.  The "5V?" column
-documents whether or not the pin is 5 volt tolerant.
+This table shows a summary of the available functionality on every
+GPIO pin, by peripheral type.  The "5 V?" column documents whether or
+not the pin is 5 volt tolerant.
 
 .. csv-table::
-   :header: Pin, STM32, :ref:`ADC <adc>`, :ref:`Timer <timers>`, :ref:`I2C <i2c>`, :ref:`UART <usart>`, :ref:`SPI <spi>`, 5v?
-
-   D0,  PA3,  ADC3,  TIM2_CH4,     -,          USART2_RX,  -,         -
-   D1,  PA2,  ADC2,  TIM2_CH3,     -,          USART2_TX,  -,         -
-   D2,  PA0,  ADC0,  TIM2_CH1_ETR, -,          USART2_CTS, -,         -
-   D3,  PA1,  ADC1,  TIM2_CH2,     -,          USART2_RTS, -,         -
-   D4,  PB5,  -,     -,            ISC1_SMBA,  -,          -,         -
-   D5,  PB6,  -,     TIM4_CH1,     I2C1_SCL,   -,          -,         Yes
-   D6,  PA8,  -,     TIM1_CH1,     -,          USART1_CK,  -,         Yes
-   D7,  PA9,  -,     TIM1_CH2,     -,          USART1_TX,  -,         Yes
-   D8,  PA10, -,     TIM1_CH3,     -,          USART1_RX,  -,         Yes
-   D9,  PB7,  -,     TIM4_CH2,     I2C1_SDA,   -,          -,         Yes
-   D10, PA4,  ADC4,  -,            -,          USART2_CK,  SPI1_NSS,  -
-   D11, PA7,  ADC7,  TIM3_CH2,     -,          -,          SPI1_MOSI, -
-   D12, PA6,  ADC6,  TIM3_CH1,     -,          -,          SPI1_MISO, -
-   D13, PA5,  ADC5,  -,            -,          -,          SPI1_SCK,  -
-   D14, PB8,  -,     TIM4_CH3,     -,          -,          -,         Yes
-   D15, PC0,  ADC10, -,            -,          -,          -,         -
-   D16, PC1,  ADC11, -,            -,          -,          -,         -
-   D17, PC2,  ADC12, -,            -,          -,          -,         -
-   D18, PC3,  ADC13, -,            -,          -,          -,         -
-   D19, PC4,  ADC14, -,            -,          -,          -,         -
-   D20, PC5,  ADC15, -,            -,          -,          -,         -
-   D21, PC13, -,     -,            -,          -,          -,         -
-   D22, PC14, -,     -,            -,          -,          -,         -
-   D23, PC15, -,     -,            -,          -,          -,         -
-   D24, PB9,  -,     TIM4_CH4,     -,          -,          -,         Yes
-   D25, PD2,  -,     TIM3_ETR,     -,          -,          -,         Yes
-   D26, PC10, -,     -,            -,          -,          -,         Yes
-   D27, PB0,  ADC8,  TIM3_CH3,     -,          -,          -,         -
-   D28, PB1,  ADC9,  TIM3_CH4,     -,          -,          -,         -
-   D29, PB10, -,     -,            I2C2_SCL,   USART3_TX,  -,         Yes
-   D30, PB11, -,     -,            I2C2_SDA,   USART3_RX,  -,         Yes
-   D31, PB12, -,     TIM1_BKIN,    I2C2_SMBA,  USART3_CK,  SPI2_NSS,  Yes
-   D32, PB13, -,     TIM1_CH1N,    -,          USART3_CTS, SPI2_SCK,  Yes
-   D33, PB14, -,     TIM1_CH2N,    -,          USART3_RTS, SPI2_MISO, Yes
-   D34, PB15, -,     TIM1_CH3N,    -,          -,          SPI2_MOSI, Yes
-   D35, PC6,  -,     -,            -,          -,          -,         Yes
-   D36, PC7,  -,     -,            -,          -,          -,         Yes
-   D37, PC8,  -,     -,            -,          -,          -,         Yes
-   D38, PC9,  -,     -,            -,          -,          -,         Yes
-   D39, PA13, -,     -,            -,          -,          -,         Yes
-   D40, PA14, -,     -,            -,          -,          -,         Yes
-   D41, PA15, -,     -,            -,          -,          -,         Yes
-   D42, PB3,  -,     -,            -,          -,          -,         Yes
+   :header: Pin, :ref:`GPIO <gpio>`, :ref:`ADC <adc>`, :ref:`Timer <timers>`, :ref:`I2C <i2c>`, :ref:`UART <usart>`, :ref:`SPI <spi>`, 5 V?
+
+   D0,  PA3,  CH3,  2_CH4,     -,       2_RX,  -,      -
+   D1,  PA2,  CH2,  2_CH3,     -,       2_TX,  -,      -
+   D2,  PA0,  CH0,  2_CH1_ETR, -,       2_CTS, -,      -
+   D3,  PA1,  CH1,  2_CH2,     -,       2_RTS, -,      -
+   D4,  PB5,  -,    -,         1_SMBA,  -,     -,      -
+   D5,  PB6,  -,    4_CH1,     1_SCL,   -,     -,      Yes
+   D6,  PA8,  -,    1_CH1,     -,       1_CK,  -,      Yes
+   D7,  PA9,  -,    1_CH2,     -,       1_TX,  -,      Yes
+   D8,  PA10, -,    1_CH3,     -,       1_RX,  -,      Yes
+   D9,  PB7,  -,    4_CH2,     1_SDA,   -,     -,      Yes
+   D10, PA4,  CH4,  -,         -,       2_CK,  1_NSS,  -
+   D11, PA7,  CH7,  3_CH2,     -,       -,     1_MOSI, -
+   D12, PA6,  CH6,  3_CH1,     -,       -,     1_MISO, -
+   D13, PA5,  CH5,  -,         -,       -,     1_SCK,  -
+   D14, PB8,  -,    4_CH3,     -,       -,     -,      Yes
+   D15, PC0,  CH10, -,         -,       -,     -,      -
+   D16, PC1,  CH11, -,         -,       -,     -,      -
+   D17, PC2,  CH12, -,         -,       -,     -,      -
+   D18, PC3,  CH13, -,         -,       -,     -,      -
+   D19, PC4,  CH14, -,         -,       -,     -,      -
+   D20, PC5,  CH15, -,         -,       -,     -,      -
+   D21, PC13, -,    -,         -,       -,     -,      -
+   D22, PC14, -,    -,         -,       -,     -,      -
+   D23, PC15, -,    -,         -,       -,     -,      -
+   D24, PB9,  -,    4_CH4,     -,       -,     -,      Yes
+   D25, PD2,  -,    3_ETR,     -,       -,     -,      Yes
+   D26, PC10, -,    -,         -,       -,     -,      Yes
+   D27, PB0,  CH8,  3_CH3,     -,       -,     -,      -
+   D28, PB1,  CH9,  3_CH4,     -,       -,     -,      -
+   D29, PB10, -,    -,         2_SCL,   3_TX,  -,      Yes
+   D30, PB11, -,    -,         2_SDA,   3_RX,  -,      Yes
+   D31, PB12, -,    -,         2_SMBA,  3_CK,  2_NSS,  Yes
+   D32, PB13, -,    -,         -,       3_CTS, 2_SCK,  Yes
+   D33, PB14, -,    -,         -,       3_RTS, 2_MISO, Yes
+   D34, PB15, -,    -,         -,       -,     2_MOSI, Yes
+   D35, PC6,  -,    -,         -,       -,     -,      Yes
+   D36, PC7,  -,    -,         -,       -,     -,      Yes
+   D37, PC8,  -,    -,         -,       -,     -,      Yes
+   D38, PC9,  -,    -,         -,       -,     -,      Yes
+   D39, PA13, -,    -,         -,       -,     -,      Yes
+   D40, PA14, -,    -,         -,       -,     -,      Yes
+   D41, PA15, -,    -,         -,       -,     -,      Yes
+   D42, PB3,  -,    -,         -,       -,     -,      Yes
+
+.. _maple-timer-map:
 
 Timer Pin Map
 ^^^^^^^^^^^^^
@@ -228,7 +241,7 @@ The following table shows which pins connect to which :ref:`EXTI lines
    * - EXTI2
      - 1, 17, 25
    * - EXTI3
-     - 0, 18
+     - 0, 18, 42
    * - EXTI4
      - 10, 19
    * - EXTI5
@@ -248,20 +261,20 @@ The following table shows which pins connect to which :ref:`EXTI lines
    * - EXTI12
      - 31
    * - EXTI13
-     - 21, 32
+     - 21, 32, 39
    * - EXTI14
-     - 22, 33
+     - 22, 33, 40
    * - EXTI15
-     - 23, 34
+     - 23, 34, 41
 
 .. _maple-usart-map:
 
 USART Pin Map
 ^^^^^^^^^^^^^
 
-The Maple has three serial ports (also known as a UARTs or USARTs):
-``Serial1``, ``Serial2``, and ``Serial3``. They communicate using the
-pins summarized in the following table:
+The Maple has three serial ports (also known as USARTs): ``Serial1``,
+``Serial2``, and ``Serial3``. They communicate using the pins
+summarized in the following table:
 
 .. csv-table::
    :header: Serial Port, TX, RX, CK, CTS, RTS
@@ -271,6 +284,24 @@ pins summarized in the following table:
    ``Serial2`` | 1  | 0  | 10 | 2  | 3
    ``Serial3`` | 29 | 30 | 31 | 32 | 33
 
+.. _maple-adc-bank:
+
+Low-Noise ADC Pins
+^^^^^^^^^^^^^^^^^^
+
+The six pins at the bottom right of the board (D15—D20) generally
+offer lower-noise ADC performance than other pins on the board. If
+you’re concerned about getting good ADC readings, we recommend using
+one of these pins to take your measurements.
+
+Maple has an electrically isolated analog power plane with its own
+regulator, and a geometrically isolated ground plane. Pins D15—D20 are
+laid out to correspond with these analog planes, and our measurements
+indicate that they generally have the lowest noise of all the analog
+lines.  However, analog performance may vary depending upon the
+activity of the other GPIOs.  Consult the :ref:`Maple hardware design
+files <maple-hardware>` for more details.
+
 Board-Specific Values
 ---------------------
 
@@ -280,11 +311,12 @@ This section lists the Maple's :ref:`board-specific values
 - ``CYCLES_PER_MICROSECOND``: 72
 - ``BOARD_BUTTON_PIN``: 38
 - ``BOARD_LED_PIN``: 13
-- ``BOARD_NR_GPIO_PINS``: 44
-- ``BOARD_NR_PWM_PINS``: 16
-- ``boardPWMPins``: 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 14, 24, 25, 27, 28
+- ``BOARD_NR_GPIO_PINS``: 44 (however, :ref:`pin D43 is not usable
+  <maple-nrst-pb4>`)
+- ``BOARD_NR_PWM_PINS``: 15
+- ``boardPWMPins``: 0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 14, 24, 27, 28
 - ``BOARD_NR_ADC_PINS``: 15
-- ``boardADCPins``: 0, 1, 2, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 27, 28
+- ``boardADCPins``: 0, 1, 2, 3, 10, 11, 12, 15, 16, 17, 18, 19, 20, 27, 28
 - ``BOARD_NR_USED_PINS``: 7
 - ``boardUsedPins``: ``BOARD_LED_PIN``, ``BOARD_BUTTON_PIN``,
   ``BOARD_JTMS_SWDIO_PIN``, ``BOARD_JTCK_SWCLK_PIN``,
@@ -309,13 +341,15 @@ This section lists the Maple's :ref:`board-specific values
 - ``BOARD_JTCK_SWCLK_PIN``: 40
 - ``BOARD_JTDI_PIN``: 41
 - ``BOARD_JTDO_PIN``: 42
-- ``BOARD_NJTRST_PIN``: 43
+- ``BOARD_NJTRST_PIN``: :ref:`43 <maple-nrst-pb4>`
+
+.. _maple-hardware:
 
 Hardware Design Files
 ---------------------
 
 The hardware schematics and board layout files are available in the
-`Maple Github repository <https://github.com/leaflabs/maple>`_.  The
+`Maple GitHub repository <https://github.com/leaflabs/maple>`_.  The
 design files for Rev 1, Rev 3, and Rev 5 are respectively in the
 ``maple-r1``, ``maple-r3``, and ``maple-r5`` subdirectories.  A
 schematic for a JTAG adapter suitable for use with Maple is available
@@ -323,7 +357,7 @@ in the ``jtagadapter`` directory.
 
 From the GitHub repository main page, you can download the entire
 repository by clicking the "Download" button.  If you are familiar
-with `git <http://git-scm.com/>`_, you can also clone the repository
+with `Git <http://git-scm.com/>`_, you can also clone the repository
 at the command line with ::
 
     $ git clone git://github.com/leaflabs/maple.git
@@ -340,18 +374,66 @@ permanently.
 * **High voltage on non-tolerant pins**: not all header pins are 5V
   compatible; so e.g. connecting certain serial devices in the wrong
   way could over-voltage the pins.  The :ref:`pin-mapping master table
-  <maple-pin-map-master>` details which pins are 5V-tolerant.
+  <maple-pin-map-master>` details which pins are 5 V tolerant.
 
 Errata
 ------
 
+This section documents design flaws and other errors.
+
 General
 ^^^^^^^
 
-* **Power Supply Marketing Mistake**: We originally sold the Maple
+.. _maple-barrel-jack:
+
+* **Barrel jack power supply voltage mistake**: The acceptable voltage
+  range given next to the barrel jack on the Maple through Rev 5s
+  manufactured in Spring 2011 is **incorrect**.  The given range is 7
+  V — 18 V.  In fact, **18 V is too high** and should not be supplied
+  to your board.  The recommended maximum voltage you should apply is
+  **12 V**.
+
+  The original voltage regulators used on the Maple were rated up to
+  18 V.  However, the voltage regulators on current Maple Revs are
+  rated up to 16 V.  Our tests indicate that they operate correctly
+  through 12 V.  We do not recommend higher input voltages.
+
+.. _maple-nrst-pb4:
+
+* **Reset and PB4 tied together**: The Maple's reset line is also
+  connected to PB4, which is labeled on the silkscreen as pin 43.
+  Thus, attempting to use pin 43 as a GPIO can reset your board.  This
+  has other implications.  Since PB4 is also the JTAG NJTRST line,
+  this prevents the :ref:`JTAG <jtag>` "reset halt" command from
+  working properly.
+
+.. _maple-power-supply:
+
+* **Power supply marketing mistake**: We originally sold the Maple
   advertising that it was capable of supplying up to 800 mA; the
   correct value is 500 mA.
 
+.. _maple-pwm-marketing:
+
+* **PWM marketing mistake**: We originally advertised the Maple as
+  having 22 PWM-capable pins; the correct number is 15.
+
+.. _maple-adc-marketing:
+
+* **ADC marketing mistake**: We originally advertised the Maple as
+  having 16 analog input pins.  Due to :ref:`the following issue
+  <maple-adc-led>`, the correct number is 15.
+
+.. _maple-adc-led:
+
+* **ADC on BOARD_LED_PIN**: We originally sold the Maple RET6 Edition
+  advertising 16 analog input lines.  However, one of them (the one on
+  pin 13) is also connected to the built-in LED.  The voltage drop
+  across the LED means that the analog to digital converter on that
+  pin is not really useful.  While it is still usable, its readings
+  will be incorrect.
+
+
 By Rev
 ^^^^^^
 
@@ -366,15 +448,6 @@ Rev 5
   from its silkscreen.  This mistake was fixed in later manufacturing
   runs.
 
-.. _maple-nrst-pb4:
-
-* **Reset and PB4 tied together**: The Maple's reset line is also
-  connected to PB4, which is labeled on the silkscreen as pin 43.
-  Thus, attempting to use pin 43 as a GPIO may reset your board.  This
-  has other implications.  Since PB4 is also the JTAG NJTRST line,
-  this prevents the :ref:`JTAG <jtag>` "reset halt" command from
-  working properly.
-
 Rev 3
 ~~~~~
 
@@ -417,16 +490,6 @@ Rev 3
   number 38 (actually 38 is connected to the BUT button). We manually
   sharpied over both of these mistakes.
 
-* **PWM Marketing Mistake**: We originally sold the Maple advertising
-  22 channels of 16-bit hardware PWM; actually the Maple only has 15.
-
-* **Reset and NJTRST tied together**: The MCU's reset pin is tied to
-  PB4, the NJTRST pin, which is pin 43.  Thus, attempting to use pin
-  43 as a GPIO will reset your board (and also prevents the JTAG
-  "reset halt") command from working properly.  It's possible to cut
-  the trace, but doing so will damage your board, so we *do not
-  recommend it* unless you're very sure about what you're doing.
-
 Rev 1
 ~~~~~
 
@@ -435,7 +498,7 @@ Rev 1
   connected to a computer).
 
   This issue was resolved in Rev 3 with a 4-layer design and a
-  geometrically isolated ADC V\ :sub:`ref` plane.
+  :ref:`geometrically isolated ADC Vref plane <maple-adc-bank>`.
 
 * **Resistors on pins 0 and 1**: these header pins, which are RX/TX on
   USART2 (:ref:`Serial2 <lang-serial>`), have resistors in-line
@@ -458,30 +521,22 @@ Rev 1
   appropriate MCU pin to Vcc; see `this forum posting
   <http://forums.leaflabs.com/topic.php?id=32#post-126>`_.
 
-* **PWM Marketing Mistake**: We originally sold the Maple advertising
-  22 channels of 16-bit hardware PWM; the correct number is 15.
-
-* **Reset and NJTRST tied together**: The MCU's reset pin is tied to
-  PB4, the NJTRST pin, which is pin 43.  Thus, attempting to use pin
-  43 as a GPIO will reset your board (and also prevents the JTAG
-  "reset halt") command from working properly.  It's possible to cut
-  the trace, but doing so will damage your board, so we *do not
-  recommend it* unless you're very sure about what you're doing.
-
 Recommended Reading
 -------------------
 
-* STMicro documentation for STM32F103RB microcontroller:
-
-    * `Datasheet
-      <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_
-      (PDF)
-    * `Reference Manual
-      <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_
-      (PDF)
-    * `Programming Manual
-      <http://www.st.com/stonline/products/literature/pm/15491.pdf>`_
-      (PDF; assembly language and register reference)
+STMicro documentation for STM32F103RB microcontroller:
+
+* `Datasheet
+  <http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00161566.pdf>`_
+  (PDF); covers STM32F103x8, STM32F103xB.
+* `Reference Manual RM0008
+  <http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/REFERENCE_MANUAL/CD00171190.pdf>`_
+  (PDF); general, definitive resource for STM32F1 line.
+* `Programming Manual PM0056
+  <http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/PROGRAMMING_MANUAL/CD00228163.pdf>`_
+  (PDF); assembly language and register reference.
+* `STM32F103RB <http://www.st.com/internet/mcu/product/164487.jsp>`_
+  overview page with links to further references.
 
 .. rubric:: Footnotes