AVR32 AP700x - I2C somewhere?

Hi,

has anyone started or completed work on an I2C driver for AP7000x?

If not, I am at least going to make SOFT I2C defines to read VPD from an At24C64 EEPROM.

Thanks, Reinhard

Am 01.06.2010 16:04, schrieb Reinhard Meyer (-VC):

Dear Reinhard Meyer,

No ...

But I've working soft-i2c here. There are still some other examples in u-boot how to interface a at24xx eeprom.

custom board config file:
---8<---
/* i2c definitions */
#define CONFIG_SOFT_I2C
#if defined(CONFIG_SOFT_I2C)
#define DEBUG_I2C
#ifndef __ASSEMBLY__
#include <asm/arch/portmux.h>
#define MEDUCORE_SDA_PIN 6
#define MEDUCORE_SCL_PIN 7

#define I2C_ACTIVE portmux_select_gpio(PORTMUX_PORT_A,
(1<<MEDUCORE_SDA_PIN), PORTMUX_DIR_OUTPUT|PORTMUX_INIT_LOW)
#define I2C_TRISTATE portmux_select_gpio(PORTMUX_PORT_A,
(1<<MEDUCORE_SDA_PIN), PORTMUX_DIR_INPUT|PORTMUX_OPEN_DRAIN)
#define I2C_READ pio_get_input_value(GPIO_PIN_PA(MEDUCORE_SDA_PIN))
#define I2C_SDA(bit) pio_set_output_value(GPIO_PIN_PA(MEDUCORE_SDA_PIN),
bit)
#define I2C_SCL(bit) pio_set_output_value(GPIO_PIN_PA(MEDUCORE_SCL_PIN),
bit)
#endif

#define I2C_DELAY udelay(3) /* TODO needs testing */
#define I2C_SOFT_DECLARATIONS

#define CONFIG_SYS_I2C_SLAVE 0x0
#define CONFIG_SYS_I2C_SPEED 100000 /* TODO needs testing */
#define CONFIG_CMD_I2C

#endif
--->8---

and in our custom board implementation (only snippet):
---8<---
@@ -29,6 +29,8 @@
#include <asm/arch/hmatrix.h>
#include <asm/arch/portmux.h>

+#include <i2c.h>
+
DECLARE_GLOBAL_DATA_PTR;

/*
@@ -71,6 +73,38 @@ static const struct sdram_config sdram_config = {

int board_early_init_f(void)
{

+       unsigned char val = 0xFF;
+       unsigned char version = 0x00;
+       int ret = -1; // assume error

+
+ // first select SCL gpio
+ portmux_select_gpio(PORTMUX_PORT_A, (1<<MEDUCORE_SCL_PIN),
PORTMUX_DIR_OUTPUT|PORTMUX_INIT_LOW);

+       // initialize i2c
+       i2c_init(1000, 0x27);
+       // check for precedence of port multiplexer
+       ret = i2c_probe(0x27);
+       if ( ret != 0 ) {

+ gd->flags |= GD_FLG_POSTFAIL;
+ goto out;
+ }
+

+       ret |= i2c_write(0x27, 0x06, 1, &val, 1); // set GPPU to FF
+       ret |= i2c_write(0x27, 0x01, 1, &val, 1); // set IPOL to FF

(invert palaritiy)
+ if ( ret != 0 ) {
+ gd->flags |= GD_FLG_POSTFAIL;
+ goto out;
+ }
+
+ ret = i2c_read(0x27, 0x09, 1, &version, 1); // read in the
version value
+ if ( ret != 0 ) {
+ gd->flags |= GD_FLG_POSTFAIL;
+ goto out;
+ }
+ // version can be used from here

--->8---

regards

Andreas Bie?mann

Thank you. That worked to verify my setup.
I was fooled by the AtTiny on the NGW100 which does try to slow I2C Transfers by pulling SCL low.
That feature however is NOT honored by the SOFT_I2C driver. So accesses to my At24C64 had to fail. After removing the AtTiny it works fine :)

The functions ACTIVE and TRISTATE are not required when the Pins are initialized OUTPUT and OPENDRAIN as follows:

int board_early_init_f(void)

{
    ...
#ifdef CONFIG_CMD_I2C
    // first select SCL and SDA gpio
    portmux_select_gpio(PORTMUX_PORT_A,(1<<SDA_PIN), 
PORTMUX_DIR_OUTPUT|PORTMUX_INIT_LOW|PORTMUX_OPEN_DRAIN);
    portmux_select_gpio(PORTMUX_PORT_A,(1<<SCL_PIN), 
PORTMUX_DIR_OUTPUT|PORTMUX_INIT_LOW|PORTMUX_OPEN_DRAIN);
    // initialize i2c
    i2c_init(1000, 0x27);
#endif
    return 0;
}

The I2C Bus by definition is a wired-or bus, all devices must have open drain outputs for SDA and SCL!

Best Regards,
Reinhard