Hello, I am trying to save my sensor data and system uptime to the external flash on my nrf5340dk. So far I have been able to erase some sectors of the external flash, write several bytes of data in it and read it out and send it over USB CDC ACM without any problem. However, when I try to erase the entire external flash (excluding the partition for mcuboot secondary), I always get the error code -5. So I tried to increment the sector number and erase each sector one by one in a loop, it turns out that the erase process failed at around 0x502000, which is 995 sectors after the mcuboot secondary partition.
Below is the code in partitions.yml that defines the external flash usage, which clearly shows the end_address (total capacity) and size (available capacity):
external_flash: address: 0x120000 device: MX25R64 end_address: 0x800000 region: external_flash size: 0x6e0000
And the loop I used in the main.c to get the erase result:
#define START_OFFSET 0x120000
#define END_OFFSET 0x800000
#define SECTOR_SIZE 4096
uint32_t number_sector = 0;
while (offset < END_OFFSET) {
ret = flash_erase(flash_dev, offset, SECTOR_SIZE);
number_sector += 1;
if (ret) {
LOG_ERR("Failed erasing at offset 0x%x after %u sectors", offset, number_sector);
return ret;
}
offset += SECTOR_SIZE;
}
Since I am always erasing the sector, so it could not be the sector alighment issue. I am assuming there is a write protection for the flash that disabled erase. I have found there is a function in zephyr called flash_ex_op but I have no idea how to use that function, and I found very limited usage example online. Could someone please help. Many thanks,
Development environment: nrf connect toolchain and sdk version 2.7.0.