FM25_SN_LEN
u8 sernum[FM25_SN_LEN];
fm25_aux_read(at25, sernum, FM25_RDSN, FM25_SN_LEN);
for (i = 0; i < FM25_SN_LEN; i++)
at25->sernum[i] = sernum[FM25_SN_LEN - 1 - i];
u8 sernum[FM25_SN_LEN];