+void motor_reply(char* slotptr, u8 code) {
+ /* returns a message of the form MXYY - X is return code, YY is motor */
+ wait_for_tx_free();
+ tx_buffer[0] = 'M';
+ tx_buffer[1] = code + '0';
+ tx_buffer[2] = *slotptr;
+ tx_buffer[3] = *(slotptr+1);
+ tx_buffer[4] = '\n';
+ tx_buffer[5] = 0;
+ send_packet();
+}
+
+void dispense_something() {
+ /* process a message VXX in msg_buf where XX is motor number */
+ u8 slot;
+
+ if ((msg_buf[1] < '0') || (msg_buf[1] > '9') ||
+ (msg_buf[2] < '0') || (msg_buf[2] > '9')) {
+ msg_buf[1] = msg_buf[2] = '0';
+ motor_reply((char*)&msg_buf[1], MOTOR_NOSLOT);
+ return;
+ }
+
+ slot = (msg_buf[1] - '0') * 10;
+ slot += msg_buf[2] - '0';
+
+ motor_reply((char*)&msg_buf[1], dispense_motor(slot));
+}
+
+void write_to_display() {
+ /* process a message in the form DXXXXXXXXXXX to send to display */
+ u8 i;
+ char buf[10];
+ for (i = 0; i < 10; i++)
+ if (msg_buf[i+1])
+ buf[i] = msg_buf[i+1];
+ else
+ break;
+
+ for (; i < 10; i++) /* pad the rest out with spaces */
+ buf[i] = ' ';
+
+ set_msg(buf);
+ send_ack();
+}
+
+void send_balance() {
+ wait_for_tx_free();
+ tx_buffer[0] = 'C';
+ tx_buffer[1] = (coin_value/10000)%10;
+ tx_buffer[2] = (coin_value/1000)%10;
+ tx_buffer[3] = (coin_value/100)%10;
+ tx_buffer[4] = (coin_value/10)%10;
+ tx_buffer[5] = coin_value%10;
+ tx_buffer[6] = '\n';
+ tx_buffer[7] = 0;
+ send_packet();
+}
+
+void give_change() {
+ u16 cost;
+
+ if ((msg_buf[1] < '0') || (msg_buf[1] > '9') ||
+ (msg_buf[2] < '0') || (msg_buf[2] > '9') ||
+ (msg_buf[3] < '0') || (msg_buf[3] > '9') ||
+ (msg_buf[4] < '0') || (msg_buf[4] > '9') ||
+ (msg_buf[5] < '0') || (msg_buf[5] > '9')) {
+ send_nack();
+ }
+ cost = msg_buf[1] - '0';
+ cost *= 10; cost = msg_buf[2] - '0';
+ cost *= 10; cost = msg_buf[3] - '0';
+ cost *= 10; cost = msg_buf[4] - '0';
+ cost *= 10; cost = msg_buf[5] - '0';
+
+ coin_cost(cost);
+ send_ack();
+}
+
+void send_keypress(u8 key) {
+ /* send a packet of the form KX with X being the key, or R for reset */
+ wait_for_tx_free();
+ tx_buffer[0] = 'K';
+ if (key == KEY_RESET)
+ tx_buffer[1] = 'R';
+ else
+ tx_buffer[1] = key+'0';
+ tx_buffer[2] = '\n';
+ tx_buffer[3] = 0;
+ send_packet();
+}
+
+void do_chime() {
+ chime_start();
+ send_ack();