Appendix A
XDT77 DUAL AM/FM TUNER
RS-232 COMMANDS
PURPOSE:
This document describes the
General Information:
Data Rate: | 19,200 baud |
Parity: | None |
Word length: | 8 data bits, 1 stop bit |
Handshake: | No RTS/CTS handshaking |
Connections: | simple 3 wire (Rx, Tx, Gnd) interface |
DATA ENTRY PROTOCOL:
The serial buss should follow a standard serial communications protocol using Line oriented ASCII data stream. The command line must be followed with a carriage return for the unit to respond. The unit should not echo characters received back to the host.
Command Codes: |
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Character | Range | Function | Example |
X: | 0,1 | Power Off / On | X1 = Power On, X0 = Power Off |
T: | 1,2 | Tuner # | T1 = Tuner 1, T2 = Tuner 2 |
B: | 1,2 | Band # | B1 = AM, Band 2 = FM |
P: | 00 - 30 | Preset # | P01 = Preset 1, P30 = Preset 30, P00 (just for status) = No Preset Selected |
F: | 4 numbers | Frequency Setting | F0890 = 890 AM, F1045 = 104.5 FM |
A: | 0,1 | Seek Up / Down | A0 = Seek Down, A1 = Seek Up |
M: | 0,1 | Step Up / Down | M0 = Step Down 1 step, M1 = Step Up 1 step |
S: | Signal Lock / | 1 = locked, 0 = not | S00 (just for status) = no signal, no stereo, S01 = invalid |
| Stereo Presence | 1 = stereo, 0 = mono | S10 = signal lock (mono), S11 = signal lock (stereo) |
Q: | Query status | ask for tuner status | Q1 = Status of Tuner 1, Q2 = Status of Tuner 2 |
| of tuner |
| Q3 = Status of both tuners, 1 then 2 |
N: | 0,1 | Preset Step Up / Down | N0 = Step Down 1 Preset, N1 = Step Up 1 Preset |
L: | 01 - 30 | Set Preset | L01 = Set Station as Preset #1 |
Command Examples:
T1B2P01<cr> would command tuner #1 to select band 2 (FM) and tune to FM preset #1
T2B1F1070L03<cr> would command tuner #2 to set AM frequency 1070 kHz as AM preset #3
This command however, would not change the current station tuned on Tuner #2
To select a station to be tuned and THEN set that station as a preset, would require two commands:
T2B1F1070<cr> would command tuner #2 to select band 1 (AM) and tune to frequency 1070 kHz.
T2L03<cr> would command tuner 2 to set the currently tuned station (in this example AM 1070) as AM preset #3
Query Example:
Q1<cr> would solicit the following response:
Feedback as to the status of tuner #1, which would include band select, station preset, frequency tuned, signal lock and stereo presence. The response string would look like this:T1B2P00F1011S11
T1 (tuner 1) B2 (FM), P00 (no preset selected), F1011 (frequency 101.1 MHz), S11 (signal lock & stereo)
Shortcut Commands:
Note: examples below are assuming Tuner 1 is in FM stereo mode and tuned to a station
Command | Response/Action |
T1N1<cr> | Tuner 1 would step up to the next higher preset number |
T1L01<cr> | Tuner 1 would set the currently tuned station as FM preset #1 |
T1S10<cr> | Tuner 1 would switch the FM mode to mono |
T1M1<cr> | Tuner 1 would step up the frequency 0.2 MHz |
T1A0<cr> | Tuner 1 would go into "seek down" mode |
T1B1<cr> | Tuner 1 would go to AM mode and tune to the last previously tuned AM station |
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