Unable to write 8210 bytes on I2c bus

RE: Unable to write 8210 bytes on I2c bus

Gaurav Dubey — Mon, 26 Apr 2021 05:16:03 GMT

Hi Jorgen,

Thanks for your help, each and every suggestion given by you helped me narrow down my issues.

I ultimately resolved the issue and able to write all the pages successfully.

I wanted to tag your second last reply as a verified answer but it doesn't show me options.

Thanks

Regards

-Gaurav

RE: Unable to write 8210 bytes on I2c bus

Jørgen Holmefjord — Fri, 23 Apr 2021 10:05:53 GMT

Hi,

Error code 16 means NRF_ERROR_INVALID_ADDR. If you are declaring 28 static buffers containing 8210 bytes, this will consume 224kB of RAM, which is almost the full RAM size of the nRF52840 (256kB).

From the API documentation for nrfx_twim_tx, you can see the reason for this error code:

NRFX_ERROR_INVALID_ADDR

The provided buffer is not placed in the Data RAM region.

Most likely, the buffers does not fit in RAM and cause some issues. Do you need to declare all buffers at once, or can you re-use the same buffer for more than one transfer? Storing the data in flash initially and copy it to one or a couple buffers while transmitting may be a better approach.

Best regards,
Jørgen

RE: Unable to write 8210 bytes on I2c bus

Gaurav Dubey — Thu, 22 Apr 2021 16:41:56 GMT

Hi Jorgen,

I migrated from code nrfx_twi to nrfx_twim successfully.

I want to write 28 pages (28 x 8210bytes) 1 page at a time.

for the same, I have made 28 static buffers in the code containing 8210 bytes in a sequence.

Now with your suggestions, I have written 13 pages successfully out of 28 but as soon as it tries to write the 14th page the function returns error code 16.

what error code 16 refers to?

how do I resolve it?

Thank you

-Gaurav

RE: Unable to write 8210 bytes on I2c bus

Jørgen Holmefjord — Thu, 22 Apr 2021 10:53:15 GMT

I believe you get this error because the function uses too long time to transfer the data when you are using the nrfx_twi driver in blocking mode, leading to a HW timeout in the driver.

I would highly recommend you to switch to using the nrfx_twim driver, as this handles the long transfers in HW, by fetching the data directly from RAM. In nrfx_twi, only one byte is provided to the peripheral by the CPU at a time, leading to much interrupt/event overhead and CPU usage. It would also be beneficial if you add an event handler in your application, to run in non-blocking mode. This would eliminate the HW timeout used in blocking mode.

RE: Unable to write 8210 bytes on I2c bus

Gaurav Dubey — Wed, 21 Apr 2021 16:25:23 GMT

Information: all other reads/writes commands are working this happens just when the buffer size is 8210 bytes

nrfx_twi_tx function call gives error code 3 only when I write 1st page of 8210 bytes for all other small transaction it is working.

Initialization in main:

//initialization:
ret_code_t err_code;
const nrfx_twi_config_t twi_max32664_config = {
.scl = ARDUINO_SCL_PIN,
.sda = ARDUINO_SDA_PIN,
.frequency = NRF_TWI_FREQ_100K,
.interrupt_priority = APP_IRQ_PRIORITY_HIGH,
.hold_bus_uninit = false
};

err_code = nrfx_twi_init(&m_twi, &twi_max32664_config, NULL, NULL);
APP_ERROR_CHECK(err_code);
nrfx_twi_enable(&m_twi);

write cmd function :

    //write command function definition
    SS_STATUS write_cmd(uint8_t *tx_buf, int tx_len, int sleep_ms) {

	me11_i2c_wakeup_call();
	ret_code_t err_code = me11_write(tx_buf, tx_len, false);

	int retries = 4;
	while (err_code != NRF_SUCCESS && retries-- > 0) {
		NRF_LOG_INFO("i2c wr retry = %d" , err_code);
		NRF_LOG_FLUSH();
		i_mxc_delay(1000);
		me11_i2c_wakeup_call();
		err_code = me11_write(tx_buf, tx_len, false);
	}

	if (err_code != 0) {
		NRF_LOG_INFO("write_cmd error SS_ERR_UNAVAILABLE = %d" , err_code);
		NRF_LOG_FLUSH();
		return SS_ERR_UNAVAILABLE;
	}

	nrf_delay_ms(sleep_ms);
	uint8_t status_byte;

	me11_i2c_wakeup_call();
	err_code = me11_read( &status_byte, 1, false);

#if 1	//optional
	bool try_again = (status_byte == SS_ERR_TRY_AGAIN);
	while ((err_code != NRF_SUCCESS || try_again) && retries-- > 0) {
		i_mxc_delay(sleep_ms * 1000);
		me11_i2c_wakeup_call();
		err_code = me11_read( &status_byte, 1, false);
		try_again = (status_byte == SS_ERR_TRY_AGAIN);
	}
#endif

	return (SS_STATUS)status_byte;

}

void me11_i2c_wakeup_call(void){

#if 1
	uint8_t tx_buf[1];
	tx_buf[0] = 0x00;


	nrfx_twi_tx(&m_twi,0x00,&tx_buf[0],1,false); //GD

	i_mxc_delay(200); //GD might need calibration

	tx_buf[0] = 0xD3;
	tx_buf[0] = 0x00;

	nrfx_twi_tx(&m_twi,0x00,&tx_buf[0],1,false); //GD
	i_mxc_delay(150);




#else

	
	uint8_t tx_buf[1] = {0xFF};
	nrfx_twi_tx(&m_twi,I2C_SLAVE_ADDR,&tx_buf[0],1,FALSE);
	nrfx_twi_tx(&m_twi,I2C_SLAVE_ADDR,&tx_buf[0],1,FALSE);
	nrfx_twi_tx(&m_twi,I2C_SLAVE_ADDR,&tx_buf[0],1,FALSE);
	nrfx_twi_tx(&m_twi,I2C_SLAVE_ADDR,&tx_buf[0],1,FALSE);
	 */

#endif

}

int me11_write( const uint8_t *data, int length, bool repeated){
	ret_code_t err_code;
	
	err_code = nrfx_twi_tx(&m_twi,I2C_SLAVE_ADDR,(uint8_t *)data, length,repeated);
	if(err_code != NRF_SUCCESS)
	{
		NRF_LOG_INFO("mel1_write err_code= %d", err_code);
//		APP_ERROR_CHECK(err_code);
	}

	return err_code;
}

int me11_read( uint8_t *data, int length, bool repeated){
	ret_code_t err_code;
	
	err_code = nrfx_twi_rx(&m_twi,I2C_SLAVE_ADDR,(uint8_t *)data, length);
	if(err_code != NRF_SUCCESS)
	{
		NRF_LOG_INFO("mel1_read err_code= %d", err_code);
//		APP_ERROR_CHECK(err_code);
	}
	return err_code;
}

calling write_cmd:

//Function call:

status = write_cmd(cmd_bytes_4c_to_205b, sizeof(cmd_bytes_4c_to_205b),340); 

//size of cmd_bytes_4c_to_205b = 8210 bytes

if(status!=SS_SUCCESS)
{
NRF_LOG_INFO("FAILED to send page bytes 0x4C to 0x205B from the .msbl file SIZE:%d status byte:0x%x",sizeof(cmd_bytes_4c_to_205b),status);
NRF_LOG_FLUSH();
}
else
{
NRF_LOG_INFO("SUCCESFULL to send page bytes 0x4C to 0x205B from the .msbl file SIZE:%d",sizeof(cmd_bytes_4c_to_205b));
NRF_LOG_FLUSH();
}

RE: Unable to write 8210 bytes on I2c bus

Jørgen Holmefjord — Wed, 21 Apr 2021 11:13:19 GMT

Error code 3 means NRF_ERROR_INTERNAL. Which function is returning this error?

Can you post your code for initializing of TWI and how you do the transfers?

RE: Unable to write 8210 bytes on I2c bus

Gaurav Dubey — Wed, 21 Apr 2021 07:38:27 GMT

Hi Jorgen,

I have migrated the code from nrf_drv_twi to nrfx_twi where API uses size_t as the length parameter.

Now when I am trying to write the bytes it sends 1380 bytes and sends error code 3.

what does error code 3 means?

RE: Unable to write 8210 bytes on I2c bus

Jørgen Holmefjord — Tue, 20 Apr 2021 14:36:05 GMT

Hi,

If you are using the nrf_drv_twi API, this uses a uint8_t parameter for the length parameters to the tx/rx functions. This variable will overflow when you exceed 255 bytes transfer length. The reasoning behind this was that nRF52832 had a hardware limitation of 255 byte transfers (8-bit length) in the TWIM peripheral. For nRF52840, this HW limitation is extended to 65535 bytes (16-bit length). To use the support for longer transfers, you need to migrate to the new nrfx drivers, which use size_t/uint32_t for the length parameters.

Best regards,
Jørgen