3 files changed, 195 insertions, 0 deletions
diff --git a/notes/dac.txt b/notes/dac.txt
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+++ b/notes/dac.txt
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+
+DAC notes (for maple native and other "high density" STM32 devices)
+-------------------------------------------------------------------------------
+There is an ST application note for the DACs; it provides a lot of context but
+doesn't help setup the peripheral very much.
+
+For the first code iteration we'll just use 12-bit right-aligned single writes, 
+so use DAC_DHR12Rx
+
+Once data is loaded into the digital registers, there are a number of possible
+triggers to start conversion to analog output: external interrupts, software
+control, and timer events. We'll just use software triggering for now.
+
+There is (obviously) DMA support for DAC output.
+
+There are noise output and triangle wave output features with variable
+amplitude.
+
+There are many additional modes to tigger output to both channels at the same
+time.
+
+Buffering will be enabled by default.
+
+TODO
+-------------------------------------------------------------------------------
+- sine wave demo using Timer interrupts
+- wirish implementation
+- documentation
+- higher performance modes?
+- signal quality testing
+- DMA output
+
diff --git a/notes/fsmc.txt b/notes/fsmc.txt
new file mode 100644
index 0000000..b41de60
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+++ b/notes/fsmc.txt
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+
+FSMC notes (for maple native and other "high density" STM32 devices)
+-------------------------------------------------------------------------------
+
+There is an application note for all this which is helpful; see the ST website.
+
+SRAM chip details
+    IS62WV51216BLL
+    512k x 16
+    19 address input
+    16 data inputs
+    t_wc (write cycle) = 55ns
+    t_rc (write cycle) = 55ns
+    t_pwe1 (write enable low pulse) = 40ns
+    t_aa (address access) = 55ns
+
+
+The FSMC nomenclature is very confusing. There are three seperate "banks"
+(which I will call "peripheral banks") each of specialized for different types
+of external memory (NOR flash, NAND flash, SRAM, etc). We use the one for
+"PSRAM" with our SRAM chip; it's bank #1. The SRAM peripheral bank is further
+split into 4 "banks" (which I will call "channels") to support multiple
+external devices with chip select pins. I think what's going on is that there
+are 4 hardware peripherals and many sections of RAM; the docs are confusing
+about what's a "block of memeory" and what's an "FSMC block".
+
+Anyways, this all takes place on the AHB memory bus.
+
+I'm going to use not-extended mode 1 for read/write.
+
+Steps from application note:
+
+- enable bank3: BCR3_MBKEN = '1'
+- memory type is SRAM: BCR3_MTYP = '00'
+- databuse weidth is 16bits: BCR3_MWID = '01'
+- memory is nonmultiplexed: BCR3_MEXEN is reset (= '0')
+- everything else is cleared
+
+But not true! Actually write enable needs to be set. 
+
+Using the application note, which is based around a very similar chip (with
+faster timing), I calculated an ADDSET (address setup) value of 0x0 and a
+DATAST (data setup) value of 0x3.
+
+Using channel1, NOR/PSRAM1 memory starts at 0x60000000.
+
+Have to turn on the RCC clock for all those GPIO pins, but don't need to use
+any interrupts.
+
+Not-super-helpful-link:
+http://www.keil.com/support/man/docs/mcbstm32e/mcbstm32e_to_xmemory.htm
+
+Note the possible confusion with address spaces, bitwidths, rollovers, etc. 
+
+
+TODO
+-------------------------------------------------------------------------------
+- more rigorous testing: throughput, latency, bounds checking, bitwidth, data
+  resiliance, etc.
+- update .ld scripts to transparently make use of this external memory
+- test/demo using a seperate external SRAM chip or screen
+- write up documentation
+
diff --git a/notes/portable.txt b/notes/portable.txt
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+++ b/notes/portable.txt
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+
+Disclaimer text:  // High-density devices only (Maple Native)
+
+
+Board portability is implemented by adding a header file to ./libmaple with the
+name of the BOARD target, and then editing libmaple.h to add this file as an
+option.
+
+A pin maple file should be added to ./notes describing the pin numbering
+
+Files to check by hand:
+#   adc.c
+#   adc.h
+#   exc.c
+#   exti.c
+#   exti.h
+#   flash.c
+#   flash.h
+#   gpio.c
+#   gpio.h
+#   libmaple_types.h
+#   nvic.c
+#   nvic.h
+#   rcc.c
+#   rcc.h
+#   ring_buffer.h
+#   rules.mk
+#   spi.c
+-   spi.h
+#   syscalls.c
+#   systick.c
+#   systick.h
+#   timers.c
+#   timers.h
+#   usart.c
+#   usart.h
+#   util.c
+#   util.h
+#   libmaple.h
+#   usb/*
+
+wirish/:
+#   bits.h
+#   boards.h
+#   cxxabi-compat.cpp
+#   ext_interrupts.c
+#   ext_interrupts.h
+#   HardwareTimer.cpp
+#   HardwareTimer.h
+#   io.h
+#   main.cxx
+#   Print.cpp
+#   Print.h
+#   pwm.c
+#   pwm.h
+#   rules.mk
+#   time.c
+#   time.h
+#   usb_serial.cpp
+#   usb_serial.h
+#   wirish_analog.c
+#   wirish.c
+#   wirish_digital.c
+#   wirish.h
+#   wirish_math.cpp
+#   wirish_math.h
+#   wirish_shift.c
+#   WProgram.h
+-   comm/
+
+
+
+ADC Notes:
+    only using ADC1?
+    untested
+
+EXTI Notes:
+    need to update huge table in comments?
+    untested
+
+NVIC Notes:
+    I don't think NVIC_ISER3 and NVIC_ICER3 actually exist?
+    Only CANBUS and USB OTG use interrupts above #63, but I updated the nvic code anyways
+
+RCC Notes:
+    Added some clock stuff to all boards even though they aren't usable... blah.
+
+SPI Notes:
+    SPI3 is only in XL chips so didn't really handle that
+
+TIMER Notes:
+    High-density devices add an advanced timer (TIMER8) and another normal one (TIMER5).
+    TIMER6 and TIMER7 are much less useful.
+    There is some partial progress towards adding timer5/timer8 functionality,
+    but not much. This should probably all be rewritten.
+    The wirish timer implementation should be refactored to use pin numbers.
+
+USART Notes:
+    The USART/UART nomeclature is a little mixed up.
+    TODO: portability of HardwareSerial, HardwareSPI