VIDEOTEK TWELVE CHANNEL SELECTOR...
WII-73 MICROWAVE TSL VIDEO/AUDIO SELECTOR
Sorry, I can not give much info, although all controls are mine.
Two videoteks are controlled by the same MCU.
Esthetically, I do not like this. But the MCU still has plenty of resources, and is not overloaded. The RS-12 is controlled by a serial connection, and the other switcher is controlled by BCD
connection: both from the same MCU module. The MCU is a "dumb" MCU and simply takes switching commands from operators.
BPS SPEED IS CHOOSEN AS 2400BPS
This switcher is controled from two cities. One city using a computer, and another city by a "remote pannel" which only has some push buttons.
THE VIDEOTEK RS-12A SWITHER CAN BE PROGRAMED FOR BCD PARRALLEL LINES, OR PROGRAMMED FOR SERIAL PACKET. SERIAL PACKET IS CHOOSEN...
BPS SPEED IS CHOOSEN AS 2400BPS
DB9-M FOR SERIAL
8 BYTES USED TO SWITCH SWITCHER
MUST CONVERT FROM 7BITS TO 8BITS
NOTE VIDEOTEK USES 7BIT CHARACTERS. USING ODD PARITY...
2 BYTES FOR ADDRESS
2 BYTES LENTH (STATIC. USE "08")
1 BYTE (STATIC. USE "D")
2 BYTES SWITCH LEVEL 00=BOTH 01=VID ONLY 02=AUD ONLY (USE "00")
2 BYTES CHANNEL (USE "0A")
2 BYTES (USE "01")
1 BYTE TAKE IT OR EXECUTE ("A")
NOTE VIDEOTEK STILL SWITCHES WITH (EXTRANEOUS) TRAILING CHARACTERS: LIKE CR OR LF
THE REQUIREMENT IS THAT THEY BE OF CORRECT PARAITY BECAUSE VIDEOTEK IS A 7BIT
SYSTEM.
USING A CONVENTIONAL 8BIT, NO PARITY...
0=CHR(30H)=0011 0000 1011 0000 =CHR(B0H) =CHR(176D)
A=CHR(41H)=0100 0001 ALREADY ODD PARITY =CHR(065D)
8=CHR(38H)=0011 1000 ALREADY ODD PARITY =CHR(056D)
1=CHR(31H)=0011 0001 ALREADY ODD PARITY =CHR(049D)
=CHR(0DH)=0000 1101 ALREADY ODD PARITY =CHR(013D)
D=CHR(44H)=0100 0100 1100 0100 =CHR(B4H) =CHR(180D)
1 BYTE LENTH PACKET X CHR(013)
2 BYTES FOR ADDRESS 00 CHR(176)+CHR(176)
2 BYTES LENTH 00 CHR(176)+CHR(056)
1 BYTE D CHR(180)
2 BYTES SWITCH LEVEL 00 CHR(176)+CHR(176)
2 BYTES CHANNEL 0A CHR(176)+CHR(065)
2 BYTES 01 CHR(176)+CHR(049)
1 BYTE TAKE IT A CHR(065)
IE: CHR(013)+CHR(176)+CHR(176)+CHR(176)+CHR(056)+CHR(180)+CHR(176)+CHR(176)+CHR(176)+
CHR(065)+CHR(176)+CHR(049)+CHR(065)
(13 CHARACTERS TOTAL, 8 DATA CHARACTERS)
THIS SELECTS CHANNEL 1
HERE IS THE CHANNEL INFORMATION USED BY THE TRANSMITTER MODULE.
BUFFERS4 IS PRE-LOADED WITH THE VIDEO CHANNEL
BUFFERS5 IS PRE-LOADED WITH THE AUDIO CHANNEL
SERCH001 ;A |
movlw D'176' ; 31 0011 0001 0011 0001 |
movwf CHANsele ;CHANNEL 1 PRE-SELECTED |
movwf Buffers4 ;VIDEO CH º
movwf Buffers5 ;AUDIO CH |
clrf STATUSmm ;CHANsele |
bsf STATUSmm,0 ;CHANsele 01 |
goto TRXSWITC
SERCH002 ;B |
movlw D'49' ; 32 0011 0010 |
movwf CHANsele ;CHANNEL 2 PRE-SELECTED |
movwf Buffers4 ;VIDEO CH º
movwf Buffers5 ;AUDIO CH |
clrf STATUSmm ;CHANsele |
bsf STATUSmm,1 ;CHANsele 02 |
goto TRXSWITC
SERCH003 ; |
goto DONEPACK ; |
HERE IS THE ACTUAL CODE FOR THE TRANSMITTER TO THE GRASS VALLEY SWITCHER.
5 CHARACTERS ARE SENT TO CHANGE VIDEO AND AUDIO CHANNEL:
CHARACTER 2 START OF PACKET PLACED IN BUFFERS1
CHARACTER 0 ADDRESS PLACED IN BUFFERS2
CHARACTER 0 ADDRESS PLACED IN BUFFERS3
VISCHANNEL (48 TO 57) CHANNEL PLACED IN BUFFERS4
AUDCHANNEL (48 TO 57) CHANNEL PLACED IN BUFFERS5
;****************************************************************************
;* *** TRX SEND CHAR MODEM SUB *** *
Both videoteks are controlled by the same MCU.
Esthitically, I don't like this. But the MCU still has plenty of resources, and is not overloaded. The RS-12 is controlled by a serial connection, and the other switcher is controlled by BCD
connection: both from the same MCU module.
CognizantWire Systems
