+u8 last_standalone;
+u8 last_switch_input;
+u8 last_misc_input;
+u16 last_coin_value;
+bool last_door_open;
+char display_buf[11];
+/* cur_motor[0] is 0 for nothing, or 1..10, or 0xff to say redraw.
+ * cur_motor[1] is 0..9 and only meaningful is cur_motor[0] != 0. */
+u8 cur_motor[2];
+
+bool check_standalone() {
+ if (is_standalone()) {
+ send_string("011 In standalone mode. Function disabled." CRLF);
+ return 1;
+ }
+ return 0;
+}
+
+void unknown_command() {
+ send_string("012 Unknown command. Type HELP for help." CRLF);
+}
+
+void motor_reply(u8 code) {
+ /* returns a message of the form MXYY - X is return code, YY is motor */
+ switch (code) {
+ case MOTOR_SUCCESS:
+ send_string("100 Vend successful." CRLF);
+ break;
+ case MOTOR_NOSLOT:
+ send_string("151 No motor there." CRLF);
+ break;
+ case MOTOR_CURRENT_FAIL:
+ send_string("152 Over current." CRLF);
+ break;
+ case MOTOR_HOME_FAIL:
+ send_string("153 Home sensors failing." CRLF);
+ break;
+ default:
+ send_string("159 Unknown motor error." CRLF);
+ }
+}
+
+void dispense_something() {
+ /* process a message VXX in sci_rx_buf where XX is motor number */
+ u8 slot;
+
+ if (check_standalone()) return;
+
+ if (my_strncmp("ALL", (char*)sci_rx_buf+1, 3)) {
+ char motor[3];
+ motor[2] = '\0';
+ send_string("102 Vend all motors starting." CRLF);
+ for (motor[0] = '0'; motor[0] <= '9'; motor[0]++) {
+ for (motor[1] = '0'; motor[1] <= '9'; motor[1]++) {
+ send_string("101 Vending ");
+ send_string(motor);
+ send_string(CRLF);
+ motor_reply(dispense_motor(motor[0]*10+motor[1]));
+ }
+ }
+ send_string("102 Vend all motors complete." CRLF);
+ return;
+ }
+
+ if ((sci_rx_buf[1] < '0') || (sci_rx_buf[1] > '9') ||
+ (sci_rx_buf[2] < '0') || (sci_rx_buf[2] > '9')) {
+ sci_rx_buf[1] = sci_rx_buf[2] = '0';
+ motor_reply(MOTOR_NOSLOT);
+ return;
+ }
+
+ slot = (sci_rx_buf[1] - '0') * 10;
+ slot += sci_rx_buf[2] - '0';
+
+ motor_reply(dispense_motor(slot));
+}
+
+void write_to_display() {
+ /* process a message in the form DXXXXXXXXXX to send to display */
+ u8 i;
+ char buf[11];
+
+ if (check_standalone()) return;
+
+ for (i = 0; i < 10; i++)
+ if (sci_rx_buf[i+1])
+ buf[i] = sci_rx_buf[i+1];
+ else
+ break;
+
+ for (; i < 10; i++) /* pad the rest out with spaces */
+ buf[i] = ' ';
+ buf[i] = '\0';
+
+ set_msg(buf);
+ send_string("300 Written." CRLF);
+}
+
+void send_balance() {
+ sci_tx_buf[0] = 'C';
+ sci_tx_buf[1] = have_change?'0':'1';
+ sci_tx_buf[2] = (coin_value/10000)%10;
+ sci_tx_buf[3] = (coin_value/1000)%10;
+ sci_tx_buf[4] = (coin_value/100)%10;
+ sci_tx_buf[5] = (coin_value/10)%10;
+ sci_tx_buf[6] = coin_value%10;
+ sci_tx_buf[8] = 0;
+ send_buffer(1);
+}
+
+void give_change() {
+ u16 cost;
+
+ if ((sci_rx_buf[1] < '0') || (sci_rx_buf[1] > '9') ||
+ (sci_rx_buf[2] < '0') || (sci_rx_buf[2] > '9') ||
+ (sci_rx_buf[3] < '0') || (sci_rx_buf[3] > '9') ||
+ (sci_rx_buf[4] < '0') || (sci_rx_buf[4] > '9') ||
+ (sci_rx_buf[5] < '0') || (sci_rx_buf[5] > '9')) {
+ send_nack();
+ }
+ cost = sci_rx_buf[1] - '0';
+ cost *= 10; cost = sci_rx_buf[2] - '0';
+ cost *= 10; cost = sci_rx_buf[3] - '0';
+ cost *= 10; cost = sci_rx_buf[4] - '0';
+ cost *= 10; cost = sci_rx_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 */
+ if (is_standalone()) return;
+
+ sci_tx_buf[0] = '2';
+ if (key == KEY_RESET) {
+ sci_tx_buf[1] = '1';
+ sci_tx_buf[2] = '1';
+ } else {
+ sci_tx_buf[1] = '0';
+ sci_tx_buf[2] = (key%10)+'0';
+ }
+ sci_tx_buf[3] = '\0';
+ send_buffer(0);
+ send_string(" key." CRLF);
+}
+
+void send_door_msg(bool open) {
+ if (is_standalone()) return;
+ sci_tx_buf[0] = '4';
+ sci_tx_buf[1] = '0';
+ sci_tx_buf[2] = open?'1':'0';
+ send_buffer(0);
+ if (open)
+ send_string(" door open." CRLF);
+ else
+ send_string(" door closed." CRLF);
+}
+
+u8 hexchar2u8(char b) {
+ if (b >= '0' && b <= '9') return b-'0';
+ if (b >= 'a' && b <= 'f') return b-'a'+0x0a;
+ if (b >= 'A' && b <= 'F') return b-'A'+0x0a;
+ return 0;
+}
+
+char nibble2hexchar(u8 b) {
+ if (b <= 9) return b+'0';
+ if (b >= 10 && b <= 15) return b+'A';
+ return 'X';
+}
+
+u8 hex2u8(char msb, char lsb) {
+ return (hexchar2u8(msb) << 4) + hexchar2u8(lsb);