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Commit Graph

12 Commits

Author SHA1 Message Date
stac
65ad2caf8a i2c: Make transaction initiator available in txn list
The info field in the pios_i2c_txn list can now be used
to provide a const string which describes the context
for this transaction.

This is very helpful when diagnosing an error that occurs
somewhere in the middle of the I2C FSM since the FSM runs
primarily in the ISR where the original context for the
transactions is no longer available in the traceback.

git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1622 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-09-15 14:20:53 +00:00
stac
98822bff98 i2c: force bus free on warm starts
Since the i2c bus is bidirectional, there are certain
states (eg. part way through a read) where the slave
device is in control of driving the SDA line.

On a cold start (power on), the slave devices are all
quiescent and will not drive the bus.  However, on a warm
start (eg. watchdog or jtag restart), it is possible that as
the CPU boots, the slave device may be holding the SDA line
low.  This is a bus busy condition and will prevent the I2C
bus master in the CPU from being able to seize the bus during
init.

The fix for this is to clock the i2c bus sufficiently to ensure
that the the slave device finishes its transaction and releases
the bus.

Once the slave has released the bus, the bus master can properly
initialize and assert a STOP condition on the bus.

git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1349 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-08-21 16:19:02 +00:00
stac
f74c6ffdd5 i2c: rewrite i2c layer
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
2010-08-08 04:15:08 +00:00
peabody124
d928676f5e More documentation updates, standardizing format to include addtogroup at the beginning of headers so files are associated with modules
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1121 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-07-16 19:53:35 +00:00
gussy
ff73ab5a80 More updates to cross-target compatibility.
Added PIOS_I2C into AHRS code.
Added PIOS_HMC5843 Module.




git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@617 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-05-12 08:18:49 +00:00
fredericg
3281b1a128 OP-27 Use RTOS in LockDevice() and UnlockDevice()
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@564 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-05-01 14:49:51 +00:00
FredericG
50215e75c6 OP-28 Some changes in the I2C API
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@296 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-03-13 12:23:55 +00:00
dankers
e66c491942 Update to headers in the flight portion of the code. Just formatting.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@276 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-03-10 09:12:31 +00:00
gussy
798ad15bba More refactoring.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@235 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-03-04 05:51:11 +00:00
fredericg
ad816dc070 Renamed PIOS_I2C_TransferBegin => PIOS_I2C_LockDevice because it better describes what it does
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@231 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-03-03 11:46:24 +00:00
gussy
3b32b89839 Updated copyright headers.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@146 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-01-31 17:56:54 +00:00
gussy
a1f7f260c1 Added PIOS_I2C module. It's blind code though, no idea if it works.
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@60 ebee16cc-31ac-478f-84a7-5cbb03baadba
2009-12-09 23:10:32 +00:00