ICDR
iic_wr(pd, ICDR, i2c_8bit_addr_from_msg(pd->msg));
iic_wr(pd, ICDR, pd->msg->buf[pd->pos]);
ret = iic_rd(pd, ICDR);
ret = iic_rd(pd, ICDR);
pd->res->start + ICDR);
pd->res->start + ICDR);