CRC error when read-write values from/to flash

[Palonso]

Hi,

I have been saving values to an ESP-WROVER-B module and sometimes, when I want to read back, I have the next error:

Code: Select all

"CRC failed"

Which only happens when the next condition is met:

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esp_partition_read(partition, index * sizeof(my_data), (void*)data_to_read, sizeof(my_data));

uint8_t crc = crc8_be(0, (const uint8_t*)data_to_read, sizeof(my_data) - 1);

if (data_to_read->crc != crc)
{
	ESP_LOGE(TAG, "CRC failed");
	return ESP_FAIL;
}

return ESP_OK;

where my_data is:

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struct
{
	uint32_t value;
	uint8_t crc;
}my_data;

I'm pretty sure everything is all right since I create data this way:

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my_data new_value;
new_value.value = its_value;
new_value.crc = crc8_be(0, (const uint8_t*)&new_value, sizeof(my_data) - 1);

and saving it with the example partition_write function.

My actual problem is that these pieces of code work fine, but sometimes I have the "CRC failed" message in the log, what could have happened?

Best regards,
P

[WiFive]

You should print the two crc values and see if you notice any pattern and also consider if you should be using wear leveling.

[Palonso]

Hi WiFive , can you explain to me a bit more about wear leveling? I didn't get what you are trying to say.

Best regards,
P

[ESP_Sprite]

Wrt WiFives wear leveling remark: Are you absolutely sure that the sector you're writing to is erased? Flash, without erasing a sector, can only ever turn 1 bits into 0 bits. If this is all you want to do, you may be better off using the NVS api, which handles the crc, erasing and wear-leveling for you.