To the outside world, the AHRS can be in one of only a few
primary states:
Not present - AHRS is absent or non-responsive via SPI
Inactive - Only link-level status messages are processed
Ready - Ready to receive the next application level message
Busy - Application level message is being processed
Internal to the AHRS, there are many more states that need to be
managed. This FSM provides the necessary decoupling between the
ISR (which is being driven by the SPI link) and the AHRS main
processing loop which must continue to run its filters independently
of the SPI messaging rate.
With this structure, SPI messages can be received at any time but
processed at only specific points within the filter chains.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1005 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
