Ad van der Weiden
The iPod controller that I submitted for the mbed challenge
Dependencies: mbed Motordriver PID
Diff: ipod.cpp
- Revision:
- 0:371773dd3dd1
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ipod.cpp Wed May 04 15:41:13 2011 +0000
@@ -0,0 +1,380 @@
+#include "mbed.h"
+#include "ipod.h"
+
+ipod::ipod(PinName tx, PinName rx): led(*new DigitalOut(DEBUGPIN)) {
+ com = new Serial(tx, rx);
+ com->baud(19200);//should work upto 57600
+ rx_ready = false;
+ tx_ready = true;
+ state = 0;
+ tx_buffer[0] = 0xff;
+ tx_buffer[1] = 0x55;
+ com->attach(this, &ipod::handlerx);
+#ifdef TX_IRQ
+ com->attach(this, &ipod::handletx, Serial::TxIrq);
+#endif
+ lastcommand = -1;
+ error = err_success;
+ replies = 0;
+}
+
+void ipod::handlerx() {//Serial port interrupt handler
+ led = 1;
+ unsigned short c = com->getc();
+// printf("%d: %02X; ", state, chk);
+ switch (state) {
+ case 0:
+ if (c==0xff) state++;
+ break;
+ case 1:
+ if (c==0x55) state++;
+ else state = 0;
+ break;
+ case 2:
+ if (rx_ready) {
+ state = 0;
+ break;//buffer not free, ignore the message
+ }
+ length = c;
+ chk = c;
+ rx_buffer = new char[length];
+ state++;
+ break;
+ case 3:
+ if (c > 4) {
+ state = 0;
+ break;//mode not known or not supported
+ }
+ mode = c;
+ chk += c;
+ state++;
+ break;
+ case 4:
+ command = c<<8;
+ chk += c;
+ state++;
+ break;
+ case 5:
+ command += c;
+ chk += c;
+ state++;
+ break;
+ default:
+ chk += c;
+ if (state < length+3) {
+ rx_buffer[state-6] = c;
+ state++;
+ } else {
+ if (chk==0) {
+ rx_ready = true;
+ replies--;
+ if (command-1 == lastcommand) {//it is a reply to lastcommand
+ //printf("reply to %02X\n", lastcommand);
+ lastcommand = -1;
+ }
+ //printf("ready %02X\n", command);
+ } else
+ printf("checksum error %02x state=%d\n", chk, state);
+ state = 0;
+ break;
+ }
+ }
+ led = 0;
+}
+
+void ipod::handletx() {
+ if (tx_index < tx_size)
+ com->putc(tx_buffer[tx_index++]);
+ else
+ tx_ready = true;
+}
+
+bool ipod::waitForReply() {//busy waits for a reply to the last issued command, all other replies are ignored
+ for (int i = 0; i < 10000000; i++) {
+ if (ready()) {
+ if (lastcommand == -1) {//indicates that a reply to the last issued command has been received
+ parse();//parse the last reply
+ return true;//return to caller for further processing
+ }
+ release();//release the buffer and hence ignore the message
+ }
+ }
+ printf("timeout: last received %02X(%d, %d, %d, \"%s\")\n", command, arg1, arg2, arg3, string);
+ error = err_timeout;
+ return false;
+}
+
+#define BIGENDIAN
+void ipod::copy(char *b, union conv p) {//copy an UINT32 argument bytewise to the buffer
+#ifdef BIGENDIAN
+ for (int i = 0; i < 4; i++)
+ *(b+3-i) = p.asBytes[i];
+#else
+ for (int i = 0; i < 4; i++)
+ *(b+i) = p.asBytes[i];
+#endif
+}
+
+void ipod::SendAirCmd(unsigned cmd, unsigned arg1, unsigned arg2, unsigned arg3) {//send an advanced ipod remote command, unused arguments are optional
+ union conv par1, par2, par3;
+ par1.asInt = arg1;
+ par2.asInt = arg2;
+ par3.asInt = arg3;
+ tx_buffer[3] = 4; //AiR mode
+ tx_buffer[4] = 0;
+ tx_buffer[5] = cmd & 0xff;
+ unsigned expect = 1; //typically expect 1 reply per request
+ switch (cmd) {
+ case 0x12: //get ipod type
+ tx_buffer[2] = 3;
+ //expect 2 bytes return
+ break;
+ case 0x14: //get iPod name
+ tx_buffer[2] = 3;
+ //expect string return
+ break;
+ case 0x16: //main lib
+ tx_buffer[2] = 3;
+ expect = 0;
+ break;
+ case 0x17: //goto item
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 8;
+ copy(tx_buffer+7, par2);
+ expect = 0;
+ break;
+ case 0x18: //get count
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 4;
+ //expect integer return
+ break;
+ case 0x1A: //get names
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 12;
+ copy(tx_buffer+7, par2);
+ copy(tx_buffer+11, par3);
+ //expect many offset,string pairs
+ expect = arg3;
+ break;
+ case 0x1C: //get time/stat
+ tx_buffer[2] = 3;
+ //expect int,int,byte
+ break;
+ case 0x1E: //get position
+ tx_buffer[2] = 3;
+ //expect int
+ break;
+ case 0x20: //get title
+ tx_buffer[2] = 7;
+ copy(tx_buffer+6, par1);
+ //expect string
+ break;
+ case 0x22: //get artist
+ tx_buffer[2] = 7;
+ copy(tx_buffer+6, par1);
+ //expect string
+ break;
+ case 0x24: //get album
+ tx_buffer[2] = 7;
+ copy(tx_buffer+6, par1);
+ //expect string
+ break;
+ case 0x26: //poll mode
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 4;
+ //expect many byte,int pairs
+ expect = 0; //the number to expect is unknown here, so either stop polling or just insert command anyway
+ break;
+ case 0x28: //run PL
+ tx_buffer[2] = 7;
+ copy(tx_buffer+6, par1);
+ expect = 0;
+ break;
+ case 0x29: //command
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 4;
+ expect = 0;
+ break;
+ case 0x2C: //get shuffle
+ tx_buffer[2] = 3;
+ //expect byte
+ break;
+ case 0x2E: //set shuffle
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 4;
+ expect = 0;
+ break;
+ case 0x2F: //get repeat
+ tx_buffer[2] = 3;
+ //expect byte
+ break;
+ case 0x31: //set repeat
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 4;
+ expect = 0;
+ break;
+ case 0x35: //get nr in PL
+ tx_buffer[2] = 3;
+ //expect int
+ break;
+ case 0x37: //goto song
+ tx_buffer[2] = 7;
+ copy(tx_buffer+6, par1);
+ expect = 0;
+ break;
+ case 0x38: //select
+ tx_buffer[6] = arg1;
+ tx_buffer[2] = 9;
+ copy(tx_buffer+7, par2);
+ tx_buffer[11] = 0;//unknown
+ break;
+ default:
+ return;
+ }
+ tx_size = tx_buffer[2] + 4;
+ tx_buffer[tx_size-1] = 0;
+ for (int i = 2; i < tx_size-1; i++)
+ tx_buffer[tx_size-1] -= tx_buffer[i];//compute checksum
+ tx_index = 1;
+ replies = expect;
+#ifdef TX_IRQ
+ while (!tx_ready) /* wait */;
+ tx_ready = false;
+ com->putc(tx_buffer[0]);//kick-off writing buffer
+#else
+ write();
+#endif
+ lastcommand = cmd;
+ printf("%02X (%d, %d, %d)\n", cmd, arg1, arg2, arg3);
+}
+
+void ipod::guarded_SendAirCmd(unsigned cmd, unsigned arg1, unsigned arg2, unsigned arg3) {//same as SendAirCmd but waits until all previous expected replies have been received
+ for (int i = 0; i<1000000; i++)
+ if (replies==0) {
+ SendAirCmd(cmd, arg1, arg2, arg3);
+ return;
+ }
+ printf("Timeout while waiting for reply to %02X, command %02X cannot be send\n", lastcommand, cmd);
+}
+
+void ipod::SetMode(int m) { //char buf[] = {0xff, 0x55, 0x03, 0x00, 0x01, 0x00, 0x00};
+ tx_buffer[2] = 3; //length
+ tx_buffer[3] = 0; //mode 0, mode switching
+ tx_buffer[4] = 1; //cmd high byte
+ tx_buffer[5] = m; //cmd low byte
+ tx_buffer[6] = 0x100 - 3 - 1 - m;//checksum
+ tx_index = 1;
+ tx_size = 7;
+#ifdef TX_IRQ
+ while (!tx_ready) /* wait */;
+ tx_ready = false;
+ com->putc(tx_buffer[0]);
+#else
+ write();
+#endif
+}
+
+unsigned ipod::copy(char* s) {//return a bytewise argument from the buffer as a UINT32
+ union conv p;
+#ifdef BIGENDIAN
+ for (int i = 0; i < 4; i++)
+ p.asBytes[3-i] = s[i];
+#else
+ for (int i = 0; i < 4; i++)
+ p.asBytes[i] = s[i];
+#endif
+ return p.asInt;
+}
+
+void ipod::parse() {
+ error = err_success;
+ switch (mode) {
+ case 0: //mode 0 reply
+ if (command & 0xFF == 4) {//reply to mode status request
+ printf("mode 0 reply = %04X\n", command);
+ } else
+ printf( "unexpected mode 0 reply\n");
+ break; //assume s.c_str()[4] == 0
+ case 4://reply to AiR command
+ switch (command) {
+ case 0:
+ if (rx_buffer[0]==0x04) {
+ error = err_unknown;
+ printf("command %04X is not understood\n", *(unsigned short*)&rx_buffer[1]);
+ }
+ break;
+ case 1:
+ error = (errors)rx_buffer[0];
+ switch (error) {
+ case err_success:
+ //printf("command %04X succeeded\n",*(unsigned short*)&rx_buffer[1]);
+ break;
+ case err_failure:
+ printf("command %04X failed\n",*(unsigned short*)&rx_buffer[1]);
+ break;
+ case err_limit:
+ printf("command %04X had wrong parameter(s)\n",*(unsigned short*)&rx_buffer[1]);
+ break;
+ case err_answer:
+ printf("command %04X is an answer\n",*(unsigned short*)&rx_buffer[1]);
+ break;
+ default:
+ printf("unknown error\n");
+ break;
+ }
+ break;
+ //2 bytes
+ case get_ipod_size+1: //ipod type
+ break;
+ //single string
+ case get_ipod_name+1:
+ case get_title+1:
+ case get_artist+1:
+ case get_album+1:
+ string = rx_buffer;
+ printf("%04X: %s\n", command, string);
+ break;
+ //number+string
+ case get_names+1:
+ string = rx_buffer + 4;
+ arg1 = copy(rx_buffer);
+ printf("%04X: %d %s\n", command, arg1, string);
+ break;
+ //number+number+byte
+ case get_time_status+1:
+ arg1 = copy(rx_buffer);
+ arg2 = copy(rx_buffer+4);
+ arg3 = rx_buffer[8];
+ printf("%04X: %d %d %02X\n", command, arg1, arg2, arg3);
+ break;
+ //number
+ case get_count+1:
+ case get_position+1:
+ case get_nr_in_playlist+1:
+ arg1 = copy(rx_buffer);
+ printf("%04X: %d\n", command, arg1);
+ break;
+ //byte + number
+ case polling+1:
+ arg1 = rx_buffer[0];
+ arg2 = copy(rx_buffer+1);
+ break;
+ //byte
+ case get_shuffle+1:
+ case get_repeat+1:
+ arg1 = rx_buffer[0];
+ printf("%04X: %02X\n", command, arg1);
+ break;
+ //10 bytes
+ case select+1: //select
+ break;
+ default:
+ printf("unsupported reply");
+ break;
+ }
+ break;
+ default:
+ printf("unsupported mode\n");
+ break;
+ }
+}
\ No newline at end of file