Interprocessor (51-51d) protocol FAQ

The 51d program running on the 7312 and the Winbond '51 chip communicate over /dev/ttyS1 at 115200 bps.

Here is what we know so far about the communications protocol:

Last byte of multi-byte strings is a checksum that appears to be calculated by (0xff - (all bytes before checksum added together) + 0x01) workable code:

unsigned char calcsum(int bytec, char bytes[])
{
  unsigned char sum=0;
  int i;
  for (i=0;i<bytec;i++) {
    sum = (sum+bytes[i])&0xff;
  }
  return (0xff-sum+1);
}

Obtained from strace at http://downloads.phathack.com/sbingner/strace-51d.log

Definitions

#define TEXT_DISK 0x00
#define TEXT_TRACK 0x01

#define SSA_MODE_NORMAL 0x00
#define SSA_MODE_ARTIST 0x01
#define SSA_MODE_GENRE 0x02
#define SSA_MODE_ALBUM 0x03

/* Codes sent from 51d to 8051 */
#define _51D_INIT 0x10         /* 4Bytes */
#define PLAYING_TRACK 0x48     /* 4Bytes: Track(2) + Disk(2) */
#define ASCII_FOLLOWS 0x50     /* 14Bytes: Type(1) + PacketNum(1) + ASCII(12) */
#define PONG 0x70              /* 0Bytes */
#define TRACKS 0x7C            /* 4Bytes: Track(2) + Disk(2) */
#define DISKS 0x7D             /* 2Bytes: Disks(2) */
#define FIRMWARE_UPLOAD 0xA3   /* 8Bytes: DATA */

/* Codes sent from 8051 to 51d */
#define SESINFO 0x11           /* 4Bytes: SSAMode(1) + RunType(1) + Lot(2) */
#define REQ_SETTINGS 0x12
#define CUR_SETTINGS 0x13      /* Not sure what this does or syntax */
#define UCID 0x14
#define PLUGIN_SET 0x15                /* 2Bytes: PWid(1) + Activate(1) */
#define REQ_TOT_TRK 0x20       /* 2Bytes: Disk(2) */
#define Q_TOT_DSK 0x21         /* 0Bytes */
#define Q_TRACK_LEN 0x22
#define PLAY 0x30              /* 6Bytes: Track(2) + Disk(2) + Offset(2) */
#define STOP 0x32              /* 0Bytes */
#define REPEAT_TRK 0x33                /* 0Bytes */
#define REPEAT_DSK 0x34                /* 0Bytes */
#define REPEAT_OFF 0x35                /* 0Bytes */
#define BEGIN_SEEK 0x36                /* 1Byte */
#define END_SEEK 0x37
#define GET_AUDIOID 0x38       /* 4Bytes: Track(2) + Disk(2) */
#define MARK_TRACK 0x39
#define RAND_ON 0x40           /* 5Bytes: ?0x0b?(1) + Track?(2) + Disk?(2) */
#define MAG_RAND_ON 0x41       /* 5Bytes: ?0x76?(1) + Track?(2) + Disk?(2) */
#define RAND_PRESS 0x43
#define MAG_RAND_PRESS 0x44
#define RAND_FORWARD 0x45      /* 0Bytes */
#define RAND_REVERSE 0x46      /* 0Bytes */
#define RAND_OFF 0x47          /* 0Bytes */
#define REQ_TRACK_NAME 0x56    /* 4Bytes: Track(2) + Disk(2) */
#define REQ_DISK_NAME 0x57     /* 2Bytes: Disk(2) */
#define STANDBY 0x60
#define SHUTDOWN 0x61          /* 0Bytes */
#define HDD_WAKEUP 0x62
#define PROG_PLD 0x63
#define PLAY_LOOPFILE 0x64
#define SYNC_REQ 0x65
#define PING 0x66              /* 0Bytes */
#define REQ_REBOOT_UC 0x67
#define UTIL_INFO 0x71
#define UTIL_HALTED 0x72
#define CUR_TEMP 0x73
#define INF_8051_REBOOTING 0x78
#define UNMUTE_DAC 0x80
#define SSA_PLAY_MODE 0x90     /* 1Byte: 0=Normal, 1=Artists, 2=Genres, 3=Albums */
#define ENTER_FEATURE 0x91
#define SEL_MENU_ITEM 0x93
#define MENU_DESCEND 0x94
#define MENU_ASCEND 0x95
#define REQ_FIRMWARE 0xA0
#define REQ_BOOT_FIRMWARE 0xA1
#define REQ_TEST_FIRMWARE 0xA2
#define INF_ARM_BOOTOK 0xB0
#define INF_51_BOOTOK 0xB1
#define INF_ERASE_OK 0xB2
#define INF_51_PROGED_OK 0xB3
#define INF_STATUS_RESULT 0xB5
#define SMALL_TRANS_PACK 0xC0
#define MED_TRANS_PACK 0xC2
#define LRG_TRANS_PACKET 0xC3
#define OLD_UTIL_INFO 0xE0
#define OLD_UTIL_HALTED 0xE1
#define UC_DEBUG 0xE2
#define OLD_REQ_FIRMWARE 0xF3
#define OLD_REQ_BOOT_FIRMWARE 0xF5
#define OLD_PROG_PLD 0xFB

/* Used globally */
#define HEADER_ACK 0xAC
#define BLOCK_ACK 0xBD
#define PACKET_ACK 0xCE
#define ERROR_DATA 0xFE
#define ERROR 0xFF

Protocol Examples

ASCII Text is sent 12 Bytes at a time, in multiple 'packets'

7312	8052	Possible Meaning
Initialization
0xf9		??
	0x53	??
0x10		??
HU Query total disc
	0x21,0xdf	Query total disc
0xce		ACK
0x7d		Total Disks follows
	0xac	OK, Continue
0x00		First byte
	0xbd	Continue
0x0f		Second Byte (total 15 disks)
	0xbd	Continue
0x74		End of Stream
	0xce	ACK
HU Query total tracks
	0x20,0x00,0x01,0xdf	Query total tracks in disc 1 (0x00, 0x01)
0xce		ACK
0x7c		Total tracks follows
	0xac	OK, Continue
0x00		First byte of total tracks
	0xbd	Continue
0x01		Second Byte of total tracks (1 track in disk 1)
	0xbd	Continue
0x00		First byte of disknum
	0xbd	Continue
0x01		Second Byte of disknum
	0xbd	Continue
0x82		End of Stream
	0xce	ACK
Direct play track
	0x30 0x00 0x01 0x00 0x02 0x00 0x00 0xcd	Play Disk 2 Track 1 Offset 0
0xce		ACK
HU ? Name of Disk
	0x57,0x00,0x02,0xa7	Name of disk 2? (Answering "PLY2: Alternative")
0xce		ACK
0x50		ACSII Follows
	0xac	OK, Continue
0x00		Type of Text (0x00 = Disk Name)
	0xbd	Continue
0x00		Packet Number
	0xbd	Continue
P		ASCII Text
	0xbd	Continue
Above 2 lines repeats for each of the letters 'LY2: Altern'
0xc9		Checksum?
	0xce	ACK
0x50		ACSII Follows
	0xac	OK, Continue
0x00		Type of Text (0x00 = Disk Name)
	0xbd	Continue
0x01		Packet Number
	0xbd	Continue
a		ASCII Text
	0xbd	Continue
Above 2 lines repeats for each of the letters 'tive'
0x00		NULL
	0xbd	Continue
Above 2 lines repeat 6 more times
0x96		Checksum?
	0xce	ACK
HU ? Name of Track
	0x56,0x00,0x01,0x00,0x02,0xa7	Name of disk 2, track 1? (returning "3 Doors Down - ")
0xce		ACK
0x50		ACSII Follows
	0xac	OK, Continue
0x01		Type of Text (0x01 = Track Name)
	0xbd	Continue
0x00		Packet Number
	0xbd	Continue
3		ASCII Text
	0xbd	Continue
Above 2 lines repeats for each of the letters ' Doors Down'
0x9d		Checksum?
	0xce	ACK
0x50		ACSII Follows
	0xac	OK, Continue
0x01		Type of Text (0x01 = Track Name)
	0xbd	Continue
0x01		Packet Number
	0xbd	Continue
0x20		ASCII Text (space)
	0xbd	Continue
Above 2 lines repeats for each of the letters ' - Duck And '
0x67		Checksum?
	0xce	ACK
0x50		ACSII Follows
	0xac	OK, Continue
0x01		Type of Text (0x01 = Track Name)
	0xbd	Continue
0x02		Packet Number
	0xbd	Continue
R		ASCII Text
	0xbd	Continue
Above 2 lines repeats for each of the letters 'Run (Live)'
0x00		NULL
	0xbd	Continue
0x00		NULL
	0xbd	Continue
0x77		Checksum?
	0xce	ACK
8052 Ping Request
	0x66, 0x9a	8052 PING
0xce		ACK
0x70		51d PONG
	0xac	ACK, Continue
0x90		Checksum
	0xce	ACK

• Heartbeat:

If the Winbond chip does not see a "heartbeat" signal every 10 seconds, it will kill power to the 7312 and reboot it. It's a two-part sequence:

7312 > 0x70
       0xAC   < 51
     > 0x90
       0xCE   < 51

Must repeat within 10 seconds, or the Winbond chip will output 0x66,0x9A 3 times and reboot.