From 5da71efa18e8b4eac9afd8bfa13e3c7e7ddde1d0 Mon Sep 17 00:00:00 2001 From: Eric Millbrandt Date: Thu, 3 Sep 2009 08:09:44 -0500 Subject: Reset i2c slave devices during init on mpc5xxx cpus Reset any i2c devices that may have been interrupted during a system reset. Normally this would be accomplished by clocking the line until SCL and SDA are released and then sending a start condtiion (From an Atmel datasheet). There is no direct access to the i2c pins so instead create start commands through the i2c interface. Send a start command then delay for the SDA Hold time, repeat this by disabling/enabling the bus a total of 9 times. Signed-off-by: Eric Millbrandt --- README | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'README') diff --git a/README b/README index c90f6ee2d..ff4ed8b95 100644 --- a/README +++ b/README @@ -1366,6 +1366,13 @@ The following options need to be configured: therefore be cleared to 0 (See, eg, MPC823e User's Manual p.16-473). So, set CONFIG_SYS_I2C_SLAVE to 0. + CONFIG_SYS_I2C_INIT_MPC5XXX + + When a board is reset during an i2c bus transfer + chips might think that the current transfer is still + in progress. Reset the slave devices by sending start + commands until the slave device responds. + That's all that's required for CONFIG_HARD_I2C. If you use the software i2c interface (CONFIG_SOFT_I2C) -- cgit v1.2.3