| Author | beginning argument ( Replies received: 1 ) |
| JakBird |
 Posted 27-06-2008 at 23:42 |
Registered on :
04-23-2007
From USA
Messages : 36
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Has anyone managed to get an interrupt driven I2C handler working, with error recovery for events such as bus errors or non-existent device? The ST example for I2C is woefuly inadequate, and the STR750 manual has virtually no information on how to recover from errors, especially a bad device address (a common occurence when enumerating devices on a common bus).
Ad hoc experiemnting shows that the AF flag is sometimes set (SR1 = 0x10, SR2 = 0x92) when a device does not respond, but this doesn't seem to happen consistently. At times I get both SR1 and SR2 set to zero in interrupts, no idea how this happens since there's no interrupt source. It doesn't occur when a valid device is found.
Perhaps there's some errata on the I2C bus?
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| jrheisey |
Posted 15-07-2008 at 02:55 |
Registered on :
01-21-2008
Messages : 4
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I was wondering whether you got you ISR based I2C communications to work.
I have implemented an ISR to track I2C errors. I've been trying to debug this but I am not seeing the issue. Here is my ISR function
Code:
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void RmiOverI2c::I2cISR(void)
{
g_uStatus = I2C_GetStatus(I2C1);
I2C_FlagClear (I2C1, I2C_EVF);
if(g_uStatus & I2C_AF) {
CI2c_Pulse(10)
I2C_FlagClear (I2C1, I2C_AF);
}
else if(g_uStatus & I2C_BERR) {
CI2c_Pulse(20)
}
else if(g_uStatus & (I2C_AF | I2C_BERR)) {
CI2c_Pulse(15)
}
}
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The ISR routine is being called from a standard IAR IRQHandler in 71x_vect.s. My problem is that the EVF won't clear even though I2C_GetStatus() accesses CR, SR1 and SR2 which is suppose to clear most if not all flags according to the STR711 reference. I watch the registers for I2C1 and do not see any changes.
Thanks,
J.R.
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STR 750 I2C error handling