/* Checksum. */
value = 0;
for (i = 0; i < PACKET_SIZE - 1; i++)
value += packet[i];
packet[i] = value & 0xff;
send_packet(sdi, packet);
/* Checksum. */
value = 0;
for (i = 0; i < PACKET_SIZE - 1; i++)
value += packet[i];
packet[i] = value & 0xff;
send_packet(sdi, packet);