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* [U-Boot-Users] SOFT_I2C on at91rm9200
@ 2007-06-18 11:39 Nils Gjerdevik
  2007-06-18 11:59 ` Joakim Tjernlund
  2007-06-18 16:27 ` Matteo Vit
  0 siblings, 2 replies; 5+ messages in thread
From: Nils Gjerdevik @ 2007-06-18 11:39 UTC (permalink / raw)
  To: u-boot

Hi,
I'm trying to store the u-boot environment in an EEPROM (at24c128) on
a custom at91rm9200 based board. This fails when using the included
HARD_I2C driver, and since there are known problems with the I2C
controller on this uC, I'm trying to set up SOFT_I2C instead, without
success so far...
This is what I've put in my config file:

#define I2C_INIT \
do { \
  *AT91C_PIOA_PER = AT91C_PA25_TWD | AT91C_PA26_TWCK; \
  *AT91C_PIOA_ODR = AT91C_PA25_TWD; \
  *AT91C_PIOA_OER = AT91C_PA26_TWCK; \
}while(0)

#define I2C_ACTIVE (*AT91C_PIOA_OER = AT91C_PA25_TWD)

#define I2C_TRISTATE (*AT91C_PIOA_ODR = AT91C_PA25_TWD)

#define I2C_READ ((*AT91C_PIOA_PDSR & AT91C_PA25_TWD) != 0)

#define I2C_SDA(bit) \
if(bit) { \
  *AT91C_PIOA_SODR = AT91C_PA25_TWD; \
} else { \
  *AT91C_PIOA_CODR = AT91C_PA25_TWD; \
}

#define I2C_SCL(bit) \
if(bit) { \
  *AT91C_PIOA_SODR = AT91C_PA26_TWCK; \
} else { \
  *AT91C_PIOA_CODR = AT91C_PA26_TWCK; \
}

#define I2C_DELAY    udelay(5)

Can anyone see what's wrong with this code?
I can access the EEPROM without problems in Linux, using the
bit-banging driver, so the board design should be OK. The code above
is(loosely) based on the Linux bit-banging driver.

Regards,
Nils

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2007-06-18 16:27 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-06-18 11:39 [U-Boot-Users] SOFT_I2C on at91rm9200 Nils Gjerdevik
2007-06-18 11:59 ` Joakim Tjernlund
2007-06-18 13:51   ` Nils N. Gjerdevik
2007-06-18 14:02     ` Joakim Tjernlund
2007-06-18 16:27 ` Matteo Vit

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