thebolt commented on issue #10853:
URL: https://github.com/apache/nuttx/issues/10853#issuecomment-1764166255
Sure. The defconfig is attached, and below is a code excerpt with the setup
of the I2C message. It's part of our RTC driver which is not 100% ready to be
publicly released, but the relevant part is:
```
#define CONFIG_RX8900_I2C_FREQUENCY 400000
#define RX8900_I2C_ADDRESS 0x32
#define RX8900_I2C_TRY_COUNT 4
#define RX8900_SEC 0x00
static int rx8900_read_regs(FAR struct rx8900_rtc_lowerhalf_s *priv,
uint8_t reg,
uint8_t count,
uint8_t *values)
{
struct i2c_msg_s msg[2] = { 0 };
int try = RX8900_I2C_TRY_COUNT;
int ret;
msg[0].frequency = CONFIG_RX8900_I2C_FREQUENCY;
msg[0].addr = RX8900_I2C_ADDRESS;
msg[0].flags = I2C_M_NOSTOP;
msg[0].buffer = ®
msg[0].length = 1;
msg[1].frequency = CONFIG_RX8900_I2C_FREQUENCY;
msg[1].addr = RX8900_I2C_ADDRESS;
msg[1].flags = I2C_M_READ;
msg[1].buffer = values;
msg[1].length = count;
/*
* There is a 61µs window during which the RTC does not acknowledge I2C
* transfers. In that case, ensure that there are multiple attempts.
*/
do {
ret = I2C_TRANSFER(priv->i2c, msg, 2);
} while ((ret == -ENXIO || ret == -EIO) && --try);
if (ret < 0) {
rtcerr("ERROR: Failed to read registers: 0x%02x..0x%02x (err %d)\n",
reg, reg + count, ret);
return ret;
}
return OK;
}
void cat(void)
{
...
int ret = rx8900_read_regs(priv, RX8900_SEC, 7, date);
...
}
```
[defconfig.txt](https://github.com/apache/nuttx/files/12915068/defconfig.txt)
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