2007/6/18, Matteo Vit matteo.vit@dave.eu:
Nils Gjerdevik ha scritto:
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...
Problem solved! Turns out the peripheral clock for the pio controller wasn't enabled. In the Linux code I looked at this was already done elsewhere. Thanks to Joakim and Matteo for valuable help. For the record, here is the code:
/* enable I2C */ #define CONFIG_SOFT_I2C 1 /* I2C bit-banged */ #define CONFIG_I2C_CMD_TREE
#define CFG_I2C_SPEED 10000 #define CFG_I2C_SLAVE 0
//Enable peripheral clock and configure data and clock pins for pio #define I2C_INIT { \ *AT91C_PMC_PCER = 1 << AT91C_ID_PIOA; \ *AT91C_PIOA_IDR = AT91C_PA25_TWD | AT91C_PA26_TWCK; \ *AT91C_PIOA_MDER = AT91C_PA25_TWD | AT91C_PA26_TWCK; \ *AT91C_PIOA_PUDR = AT91C_PA25_TWD | AT91C_PA26_TWCK; \ *AT91C_PIOA_ODR = AT91C_PA25_TWD | AT91C_PA26_TWCK; \ *AT91C_PIOA_PER = AT91C_PA25_TWD | AT91C_PA26_TWCK; \ }
//Configure data pin as output #define I2C_ACTIVE (*AT91C_PIOA_OER = AT91C_PA25_TWD)
//Configure data pin as input #define I2C_TRISTATE (*AT91C_PIOA_ODR = AT91C_PA25_TWD)
//Read data pin #define I2C_READ (*AT91C_PIOA_PDSR & AT91C_PA25_TWD ? 1 : 0)
//Set data pin #define I2C_SDA(bit) *AT91C_PIOA_OER = AT91C_PA25_TWD; \ if (bit) *AT91C_PIOA_SODR = AT91C_PA25_TWD; \ else *AT91C_PIOA_CODR = AT91C_PA25_TWD
//Set clock pin #define I2C_SCL(bit) *AT91C_PIOA_OER = AT91C_PA26_TWCK; \ if (bit) *AT91C_PIOA_SODR = AT91C_PA26_TWCK; \ else *AT91C_PIOA_CODR = AT91C_PA26_TWCK
#define I2C_DELAY udelay(2) /* 1/4 I2C clock duration */
The env_in_eeprom config is: #define CFG_ENV_IS_IN_EEPROM 1 #define CFG_ENV_OFFSET 0 /* Env in the beginning of EEPROM */ #define CFG_ENV_SIZE 0x800 /* 2kb */ #define CFG_I2C_EEPROM_ADDR 0x50 /* Default EEPROM address */ #define CFG_EEPROM_PAGE_WRITE_BITS 6 /* 64 byte page size */ #define CFG_EEPROM_PAGE_WRITE_DELAY_MS 5 /* 5ms delay between page writes */ #define CFG_I2C_EEPROM_ADDR_LEN 2 /* 2 bytes used for addressing in the EEPROM */ #define CFG_EEPROM_SIZE 0x4000 /* 16kb */
Nils