flashwrite example

[etamar]

Hi, I am a bit confused from the example, in the specs it is said that writing the flash is word allign, and even so the example does something strange:

    do

    {
        NRF_LOG_INFO("Enter char to write to flash\r\n");
        NRF_LOG_FLUSH();
        // Read char from uart, and write it to flash:
        patwr = NRF_LOG_GETCHAR();

        if (patold != patwr)
        {
            patold = patwr;
            flash_word_write(addr, (uint32_t)patwr);
            ++addr;
            i += sizeof(patwr);
            NRF_LOG_INFO("'%c' was written to flash\r\n", patwr);
        }
        // Read from flash the last written data and send it back:
        patrd = (uint8_t)*(addr - 1);
        NRF_LOG_INFO("'%c' was read from flash\r\n\r\n", patrd);
        NRF_LOG_FLUSH();
    }
    while (i < pg_size);

every iteration i is incremented by sizeof(patwr), which is 8 and not 32, and addr is incremented by 32(++addr) which can result in an overflow.

Did I miss anything and it should work fine?

[AlekseyJ]

nRF51 and nRF52 SoC is built around a 32-bit ARM Cortex. Cortex ARM is a 32 bit processor. 32 bit equal to one word. One word is 4 bytes. sizeof(patwr) equal to 1 byte. ++addr equal to ++4 bytes. (uint32_t)patwr equal to 4 bytes of data, just first 3 bytes will be 0. Word aligned mean that it should be 4 bytes data length and also should be word-aligned address.

[etamar]

pg_size is given in bytes(i maybe mistaken) , not in words- because the addr is determined by (pg_size * pg_num)

i(in bytes) is compared to pg_size (words)

[AlekseyJ]

nRF51 page size 256 words or 1024 bytes. nRF52 page size 1024 words or 4096 bytes. I also agree with you that here is error in the code. Instead i += sizeof(patwr); should be i += sizeof(addr);.

[Petter Myhre]

I agree with your guys, I have reported it.