The STM32 I2C block has a number of errata associated with it.
These errata are primarily related to timing sensitivities between
the peripheral and the interrupt handler. In particular, the
correct generation of the stop bit relies on the I2C IRQ running
immediately and not being held off for any reason.
NOTE: The I2C interrupts must be the highest priority IRQs in the
system to ensure correct operation.
I2C protocol is now implemented as a formal state machine.
See: stm32_i2c_fsm.{dot,jpg} for FSM description.
I2C init is now expressed by const initializers in pios_board.c
for both OP and AHRS boards.
I2C device drivers (ie. bmp085/hmc5843) now pass in const arrays
of an unlimited number of bus transfers to be done atomically.
The I2C adapter driver now handles all bus-level locking across the
list of transactions. Generation of start/restart/stop conditions
are handled automatically over the list of transactions.
Timeouts have been removed from the API for now. May be added
back later.
This driver has run error free on both the OP and AHRS boards for
up to 48hrs but it still sometimes fails earlier than that on the OP
board. There is another possible set of improvements to the driver
that could employ the DMA engine for transfers of >= 2bytes. This
change would reduce the timing sensitivities between the peripheral
and the driver but unfortunately, both the SPI and I2C interfaces
share the DMA1 engine. That means only one of these two peripherals
can use the DMA engine and right now, SPI between OP and AHRS is
already using it.
Failures are currently fatal and will lock up the CPU. This allows
useful information to be obtained in the failure cases.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1241 ebee16cc-31ac-478f-84a7-5cbb03baadba
- syntax error in pios_board_posix.c introduced with Doxygen comment blocks
- platform dependant code had been added to openpilot.c instead of pios_board.c
- redundant header inclusion (stm32... already included by PiOS)
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1171 ebee16cc-31ac-478f-84a7-5cbb03baadba
PIOS SPI devices may now make use of automatic CRC generation
and checking on block transfers. Only supports CRC8 for now.
Since the SPI interface CRC calculation continues across message
boundaries (ie. not reset on every transfer), we must manually reset
the CRC registers for every transfer to allow the two sides of the
link to resynchronize.
Unfortunately, resetting the CRC registers requires disabling the
SPI peripheral which must now be done on every block transfer.
Note: The last byte of the tx buffer is never sent and is assumed to
be a place holder for the tx CRC8.
Note: The last byte of the rx buffer is expected to hold the rx CRC8.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1011 ebee16cc-31ac-478f-84a7-5cbb03baadba
The input data lines between the OP and AHRS boards had internal
pull-ups enabled. This seemed to be causing issues early on
during development of the inter-board comms. Not sure if this
is still necessary but this is how the current code was tested.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1006 ebee16cc-31ac-478f-84a7-5cbb03baadba
Mark the device specific DMA IRQ handlers as strongly linked
aliases for the genericly named interrupt vector symbol.
Here's how this works...
* The address of the symbol DMA1_Channel2_IRQHandler is written
into the DMA1/Channel2 interrupt vector by the linker script.
* The startup_*.S file specifies Default_Handler() as a weakly
linked alias for DMA1_Channel2_IRQHandler.
* We now override the weakly linked alias with the strongly linked
PIOS_SPI_sdcard_irq_handler().
* This results in the address of PIOS_SPI_sdcard_irq_handler() being
written to the vector table for the DMA1/Channel2 interrupt.
* The PIOS_SPI_sdcard_irq_handler() function is now called whenever
the DMA1/Channel2 interrupt fires.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1003 ebee16cc-31ac-478f-84a7-5cbb03baadba
- Created a pluggable COM layer
- Converted COM + USART init into static initializers
rather than typedefs
- Generalized the USB HID COM API to match the USART
API.
- Changed USART and COM layers to be data driven rather
than #ifdef'ing/switching on the specifics of each port
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@760 ebee16cc-31ac-478f-84a7-5cbb03baadba
Added support for SPI slave configurations to the pios SPI layer.
Converted the board specific configuration for the PIOS SPI layer to
use const static initializers rather than #defines (see pios_board.c).
SPI interface between the OP board and the AHRS is now operational at
a basic level, capable of moving simple single byte messages between
boards. Multi-byte, CRC protected messages will be added on top of this.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@759 ebee16cc-31ac-478f-84a7-5cbb03baadba
