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-.. highlight:: sh
-
-.. _maple:
-
-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: :ref:`STM32F103RBT6 <maple-stdocs>`, a 32-bit ARM Cortex M3
- microprocessor
-* Clock Speed: **72 MHz**
-* **128 KB Flash** and **20 KB SRAM**
-* 43 :ref:`digital I/O pins (GPIOs) <gpio>`
-* 15 :ref:`PWM <pwm>` pins at 16 bit resolution
-* 15 :ref:`analog input (ADC) <adc>` pins at 12-bit resolution
-* 2 :ref:`SPI <spi>` peripherals
-* 2 :ref:`I2C <i2c>` peripherals
-* 7 Channels of Direct Memory Access (**DMA**) (:ref:`libmaple-dma`)
-* 3 :ref:`USART (serial port) <usart>` peripherals
-* One advanced and three general-purpose :ref:`timers <timers>`
-* Dedicated :ref:`USB <usb>` port for programming and communications
-* :ref:`JTAG <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:`Open source, 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:
-
-Identifying your Rev
---------------------
-
-We went through three versions ("Revs") of the Maple hardware: Rev 1,
-Rev 3, and Rev 5 [#frev2_4]_; Rev 5, the final design, is currently on
-sale. The following sections will help you to help you identify your
-Rev.
-
-Rev 5
-^^^^^
-
-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
-necessitated the removal of pins 21 and 22 from the double header;
-they are still available, but don't have any headers installed on
-them.
-
-.. figure:: /_static/img/maple_rev5.png
- :align: center
- :alt: Maple Rev 5
-
-Rev 3
-^^^^^
-
-This batch of boards went on sale beginning in May 2010. They have a
-darker red silkscreen and the "infinity leaf" logo. The Maple Rev 3
-was the first version which includes the built-in button, labeled BUT.
-
-.. figure:: /_static/img/maple_rev3.png
- :align: center
- :alt: Maple Rev 3
-
-Rev 1
-^^^^^
-
-A small number of Maple Rev 1 boards went on sale in late 2009. They
-have a light red silkscreen and a single pixelated leaf as a logo.
-
-.. figure:: /_static/img/maple_rev1.png
- :align: center
- :alt: Maple Rev 1
-
-.. _maple-powering:
-
-Powering the Maple
-------------------
-
-The Maple's power source is determined by the header to the left of
-the "LeafLabs" label on the silkscreen. All versions of the Maple can
-be powered from the barrel jack connector, USB, or a LiPo battery. We
-ship the Maple with a jumper on the USB selector. In order to power
-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. 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.
-
-When powering the board from a barrel jack, **double check the
-polarity of the barrel.** The appropriate polarity is noted on the
-silkscreen right next to the connector.
-
-.. warning:: Silkscreens on Maples up through Rev 5s manufactured in
- Spring 2011 falsely indicated that the barrel jack could be
- supplied by up to 18V. (Rev5s manufactured after Spring 2011 may
- still have this error on the silk, but it has been marked over.) We
- recommend a barrel jack input voltage **no greater than 12V**, and
- potentially even lower depending upon the current draw requirements
- of the application. The same goes for powering off LiPo batteries.
-
- Please see :ref:`Power Regulation on the Maple
- <maple-power-regulation>` for more information.
-
-.. _maple-power-regulation:
-
-Power Regulation on the Maple
------------------------------
-
-Power regulation on the Maple is provided by two low dropout linear
-voltage regulators. (The part is the MCP1703 from Microchip, in the
-SOT-23A package. You can download the datasheet `here
-<http://ww1.microchip.com/downloads/en/DeviceDoc/22049a.pdf>`_ ). One
-of the regulators supplies power to the digital voltage plane; the
-other supplies power to the analog voltage plane.
-
-These voltage regulators nominally take an input of up to 16V. In
-addition, while the maximum continuous output current for the board is
-250mA, if you are powering the board off higher voltages the current
-it can supply goes down, due to the regulators needing to dissipate
-the extra power. So if you are powering the board off 12V, the max
-current is about 40mA at room temperature. In general (again, at room
-temperature) the max power dissipation (PD) for the chip is about
-.37W, and output current = PD/(Vin-Vout). For exact max current
-calculations, please refer to the datasheet linked above.
-
-If you are planning to draw a lot of current from the Maple board, it
-is necessary to provide input power as close to 3.3V as
-possible. Powering the microcontroller circuitry and LEDs on the board
-alone takes approximately 30mA, so if you are powering the board with
-12V that leaves only 10mA (at best) available for powering any user
-circuitry. Attempting to draw more than 10mA runs the risk of shorting
-out the power regulators and bricking your board.
-
-Using the Built-in Battery Charger
-----------------------------------
-
-Maples Rev 3 and Rev 5 also have a built-in LiPo battery charger. In
-order to use it, put a jumper across the CHRG header on the power
-selection header and across the USB, or EXT selectors, depending on
-whether you're charging the battery via USB cable or barrel jack
-connector. The LED labeled CHRG will light up while the battery is
-being charged. When the battery is finished charging, the LED labeled
-DONE will light up.
-
-.. _maple-gpios:
-
-GPIO Information
-----------------
-
-The Maple features 38 ready-to-use general purpose input/output (see
-:ref:`gpio`) pins for digital input/output, numbered ``D0`` through
-``D37``. These numbers correspond to the numeric values next to each
-header on the Maple silkscreen.
-
-.. _maple-ret6-but:
-
-Pin ``D38`` is the board's :ref:`button pin <lang-board-values-but>`.
-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`` 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
-
-.. _maple-pin-map-master:
-
-Master Pin Map
-^^^^^^^^^^^^^^
-
-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 :ref:`5 volt tolerant <gpio-5v-tolerant>`.
-
-Note that this table is not exhaustive; on some pins, more peripherals
-are available than are listed here.
-
-.. csv-table::
- :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-gpio-port-map:
-
-GPIO Port Pin Map
-^^^^^^^^^^^^^^^^^
-
-The following table shows what pins are associated with each
-:ref:`GPIO port <gpio-ports>`.
-
-.. csv-table::
- :header: GPIOA, GPIOB, GPIOC
-
- PA0: D2, PB0: D27, PC0: D15
- PA1: D3, PB1: D28, PC1: D16
- PA2: D1, PB2: -, PC2: D17
- PA3: D0, PB3: D42, PC3: D18
- PA4: D10, PB4: D43, PC4: D19
- PA5: D13, PB5: D4, PC5: D20
- PA6: D12, PB6: D5, PC6: D35
- PA7: D11, PB7: D9, PC7: D36
- PA8: D6, PB8: D14, PC8: D37
- PA9: D7, PB9: D24, PC9: D38
- PA10: D8, PB10: D29, PC10: D26
- PA11: -, PB11: D30, PC11: -
- PA12: -, PB12: D31, PC12: -
- PA13: D39, PB13: D32, PC13: D21
- PA14: D40, PB14: D33, PC14: D22
- PA15: D41, PB15: D34, PC15: D23
-
-.. _maple-timer-map:
-
-Timer Pin Map
-^^^^^^^^^^^^^
-
-The following table shows what pins are associated with a particular
-timer's capture/compare channels.
-
-.. csv-table::
- :header: Timer, Ch. 1, Ch. 2, Ch. 3, Ch. 4
- :delim: |
-
- 1 | D6 | D7 | D8 | -
- 2 | D2 | D3 | D1 | D0
- 3 | D12 | D11 | D27 | D28
- 4 | D5 | D9 | D14 | D24
-
-.. _maple-exti-map:
-
-EXTI Line Pin Map
-^^^^^^^^^^^^^^^^^
-
-The following table shows which pins connect to which :ref:`EXTI lines
-<external-interrupts-exti-line>` on the Maple.
-
-.. list-table::
- :widths: 1 1
- :header-rows: 1
-
- * - EXTI Line
- - Pins
- * - EXTI0
- - D2, D15, D27
- * - EXTI1
- - D3, D16, D28
- * - EXTI2
- - D1, D17, D25
- * - EXTI3
- - D0, D18, D42
- * - EXTI4
- - D10, D19
- * - EXTI5
- - D4, D13, D20
- * - EXTI6
- - D5, D12, D35
- * - EXTI7
- - D9, D11, D36
- * - EXTI8
- - D6, D14, D37
- * - EXTI9
- - D7, D24, D38
- * - EXTI10
- - D8, D26, D29
- * - EXTI11
- - D30
- * - EXTI12
- - D31
- * - EXTI13
- - D21, D32, D39
- * - EXTI14
- - D22, D33, D40
- * - EXTI15
- - D23, D34, D41
-
-.. _maple-usart-map:
-
-USART Pin Map
-^^^^^^^^^^^^^
-
-The Maple has three serial ports (also known as :ref:`USARTs
-<usart>`): ``Serial1``, ``Serial2``, and ``Serial3``. They communicate
-using the pins given in the following table.
-
-.. csv-table::
- :header: Serial Port, TX, RX, CK, CTS, RTS
- :delim: |
-
- ``Serial1`` | D7 | D8 | D6 | |
- ``Serial2`` | D1 | D0 | D10 | D2 | D3
- ``Serial3`` | D29 | D30 | D31 | D32 | D33
-
-.. _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
----------------------
-
-This section lists the Maple's :ref:`board-specific values
-<lang-board-values>`.
-
-- ``CYCLES_PER_MICROSECOND``: 72
-- ``BOARD_BUTTON_PIN``: 38
-- ``BOARD_LED_PIN``: 13
-- ``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, 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
-- ``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``: 2
-- ``BOARD_SPI1_NSS_PIN``: 10
-- ``BOARD_SPI1_MOSI_PIN``: 11
-- ``BOARD_SPI1_MISO_PIN``: 12
-- ``BOARD_SPI1_SCK_PIN``: 13
-- ``BOARD_SPI2_NSS_PIN``: 31
-- ``BOARD_SPI2_MOSI_PIN``: 34
-- ``BOARD_SPI2_MISO_PIN``: 33
-- ``BOARD_SPI2_SCK_PIN``: 32
-- ``BOARD_JTMS_SWDIO_PIN``: 39
-- ``BOARD_JTCK_SWCLK_PIN``: 40
-- ``BOARD_JTDI_PIN``: 41
-- ``BOARD_JTDO_PIN``: 42
-- ``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
-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
-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
-at the command line with ::
-
- $ git clone git://github.com/leaflabs/maple.git
-
-.. _maple-failure-modes:
-
-Failure Modes
--------------
-
-The following are known failure modes. The failure modes aren't
-design errors, but are easy ways to break or damage your board
-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 :ref:`5 V tolerant
- <gpio-5v-tolerant>`.
-
-Errata
-------
-
-This section documents design flaws and other errors.
-
-General
-^^^^^^^
-
-.. _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 7V
- — 18V. In fact, **18V is too high** and should not be supplied to
- your board. The original voltage regulators used on the Maple were
- rated up to 18V. However, the voltage regulators on current Maple
- Revs are rated up to only 16V, and due to the current draw
- requirements of the board, operate properly only up to 12V. The
- recommended maximum voltage you should apply is **12V**, and
- potentially even lower depending upon the current draw requirements
- of the application. Please see :ref:`Power Regulation on the Maple
- <maple-power-regulation>` for more information.
-
-.. _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
-^^^^^^
-
-The following subsections lists known issues and warnings for each
-revision of the Maple board.
-
-Rev 5
-~~~~~
-
-* **Pin 3 AIN missing**: Pin 3 is capable of analog input, but on Rev
- 5s manufactured during Fall 2010, the corresponding "AIN" is missing
- from its silkscreen. This mistake was fixed in later manufacturing
- runs.
-
-Rev 3
-~~~~~
-
-* **Pin 3 AIN missing**: Pin 3 is capable of analog input, but the
- corresponding "AIN" is missing from the Rev 3 silkscreen.
-
-.. _maple-rev3-bad-buttons:
-
-* **Bad/Sticky Buttons**: a number of Rev 3 boards sold in May-June 2010
- have questionable RESET and BUT buttons.
-
- What seems to have happened is that the flux remover we used to
- clean the boards before shipping eroded the plastic internals, which
- resulted in intermittent functionality. All buttons on all shipped
- boards did function in testing, but some may have been unreliable in
- regular use.
-
- If you have this problem, we will be happy to ship you new buttons
- if you think you can re-solder them yourself, or you can ship us
- your board and we will swap out that part.
-
- For reference, the button part number is KMR211GLFS and the flux
- remover we used is "Precision Electronics Cleaner" from RadioShack,
- which is "Safe on most plastics" and contains: dipropylene glycol
- monomethyl ether, hydrotreated heavy naphtha, dipropylene glycol
- methyl ether acetate (say that three times fast!), and carbon
- dioxide.
-
-* **Resistors on pins 0 and 1**: these header pins, which are RX/TX on
- USART2 (:ref:`Serial2 <lang-serial>`), have resistors in-line
- between the STM32 and the headers. These resistors increase the
- impedance of the lines for ADC reads and affect the open drain GPIO
- functionality of the pins.
-
- These resistors were accidentally copied over from older Arduino USB
- designs, where they appear to protect the USB-Serial converter from
- TTL voltage on the headers.
-
-* **Silkscreen Errors**: the silkscreen on the bottom indicated PWM
- functionality on pin 25 and listen the external header GND pin as
- number 38 (actually 38 is connected to the BUT button). We manually
- sharpied over both of these mistakes.
-
-Rev 1
-~~~~~
-
-* **ADC noise**: generally very high, in particular when the USB port
- is being used for communications (including keep-alive pings when
- connected to a computer).
-
- This issue was resolved in Rev 3 with a 4-layer design and a
- :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
- between the STM32 and the headers. These resistors increase the
- impedance of the lines for ADC reads and affect the open drain GPIO
- functionality of the pins.
-
- These resistors were accidentally copied over from older Arduino USB
- designs, where they appear to protect the USB-Serial converter from
- TTL voltage on the headers.
-
-* **Silkscreen Differences**: the pin numbering scheme on Rev 1 is
- different from Rev 3, and thus Rev 3 software is difficult to use
- with Rev 1 boards. Notably, the analog input bank is labeled A0-A4
- on Rev 1 but 15-20 on Rev 3, and the extra header bank does not have
- a pinout table on the bottom.
-
-* **No BUT Button**: the BUT button, useful for serial bootloading,
- was only added in Rev 3. As a workaround, you can directly short the
- appropriate MCU pin to Vcc; see `this forum posting
- <http://forums.leaflabs.com/topic.php?id=32#post-126>`_.
-
-Recommended Reading
--------------------
-
-.. _maple-stdocs:
-
-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); definitive resource for peripherals on the 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
-
-.. [#frev2_4] Revs 2 and 4 were prototypes that didn't pass internal
- testing.