Initial timer refactor.

Basic PWM works.  Had some problems in testing that might be due to
USART bugs.

HardwareTimer has been removed from the build for now; I will
re-implement it in terms of the new libmaple API, but consider it
deprecated.  Let's come up with something better.

Servo is implemented in terms of HardwareTimer, so it also has been
temporarily removed from the build.

pwmWrite() likely got a little bit less inefficient due to
indirection, but the PIN_MAPs shrank by a pointer per PinMapping.

3 files changed, 17 insertions, 90 deletions

diff --git a/notes/portable.txt b/notes/portable.txt
index 69952d7..cc1f2ac 100644
--- a/notes/portable.txt
+++ b/notes/portable.txt
@@ -1,98 +1,28 @@
+Board portability is implemented in boards.h, libmaple.h, and stm32.h.
 
-Disclaimer text:  // High-density devices only (Maple Native)
+At compile time, we currently expect one of STM32_MEDIUM_DENSITY or
+STM32_HIGH_DENSITY to be defined.  There's no support for low-density
+chips.  XL-density isn't in the near horizon; patches welcome.  You'll
+also need to define some BOARD_foo if you expect to use Wirish; this
+comes along with some additional assumptions about your board's layout.
 
+The code in usb/ is not very portable at all right now; expect this to
+change in the future, but for now, we're focusing on rolling out a
+more complete backend.
 
-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
+A file should be added to ./notes describing the pin numbering of any
+new board you add.
 
 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
+    SPI3 is only in XL chips, so we don't 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:
diff --git a/notes/usb.txt b/notes/usb.txt
index 5e00354..9552b9f 100644
--- a/notes/usb.txt
+++ b/notes/usb.txt
@@ -1,3 +1,7 @@
+XXX
+XXX This file may be out of date!
+XXX
+
 [NOTE: this is a long term proposal. The current implementation just does a 
 2ms TIMEOUT]
 
diff --git a/notes/vga.txt b/notes/vga.txt
index d75281a..43b6830 100644
--- a/notes/vga.txt
+++ b/notes/vga.txt
@@ -7,8 +7,7 @@ gpio_write_bit() is about 360ns (2.78MHz)
 
 Writing to GPIO?_BASE is about 60ns (16.6MHz -> 18MHz)
 
-pwm write 0x0001 is about 30ns (33MHz) with prescaler as 1 (default)
-pwm write 0x0001 is about 14ns (72MHz) with prescaler as 0 (!)
+PWM write 0x0001 is about 14ns (72MHz) with prescaler as 0 (!)
 
 VGA Timing
 ------------------------------------------------------------------------------
@@ -34,9 +33,3 @@ Crude 640x480 directions:
     11 lines front porch
     2 lines Vsync (low)
     31 lines back porch
-
-Currently, setting vs. clearing GPIO registers seems to take a different amount
-of time? Or perhaps i'm not analyzing branching correctly. Regardless, if you
-SET 100x times then UNSET on one line, then UNSET 100x then SET the next line,
-the two changes in color will generally not line up. 
-