Project #1   - Jerrold data stream logger in under 288 bytes!
 

First, GI sends its data manchester encoded on a carrier anywhere from 80Mhz to 122.7 in some places. Once you STRIP the manchester encoding you get a standard 11 bit packet containing 1 start bit, 8 data bits, 1 even parity bit, 1 stop bit. Years ago GI actually stripped the manchester data off the incoming packets and sent them to a standard 6850 uart. Now adays they use an advanced 6850 core in their custom chip to convert the data. Fortunately, we all have 16450/16550 usarts in our PC's which HAPPILY read the data coming in off the cable wire (with help).
 
 

First problem, how to convert the manchester data to standard data (polar).

Manchester looks like this:
 

We want it to look like this (for our PC):
 

Looks difficult??? Not really, notice the transistion between 1 and 0 above. (manchester). If we sample for that then we KNOW when a one or 1 is going to happen (this allows us to lock onto the data coming in).

This is what the data looks like in the real world:

Now, back to our problem. The easiest method is to use a pic.... Well, here is the SOURCE CODE:

-------------------------------------------------------------------------------------------------
; Magicboxes 1998 Jerrold Data Logger - 1998
; This is copyright material. This software may be freely
; distributed as long as the headers are in tact!

                device  pic16c54,xt_osc,wdt_off,protect_off
 
 

temp1    equ    10h               ;Counter for serial delay routines
 

DataIn  equ     porta.2
DataOut equ     porta.3
 

                RESET  BEGIN
 
 
 

                org 10
BEGIN
                movlw   11110111b
                tris  porta     ; RA.2 is the RS232 output.
 

        bcf     DataOut
restart movlw   19              ; wait for approx 60us high
        movwf   temp1           ; this flips the manchester encoding
start
        btfss   DataIn
        goto    restart
        decfsz  temp1,1
        goto    start
        goto    loop1           ; wait for a 0 bit
 

; the loop below runs endlessly converting manchester data to unipolar data !

loop0                           ; wait for a 1 bit
        btfss   DataIn
        goto    loop0
        bcf     DataOut
        goto    wait60

loop1                           ; wait for a 0 bit
        btfsc   DataIn
        goto    loop1
        bsf     DataOut
        goto    wait60

wait60                          ; wait 50uS
        movlw   32
        movwf   temp1
loop2   decfsz  temp1,1
        goto    loop2
        nop

        btfsc   DataIn         ; check to see current status of new bit, jmp accordingly
        goto    loop1
        goto    loop0
 
 
 

The circuit:

When you burn a PIC16C54 and build this circuit you should see:

Trace 1 is the data coming into the PIC16C54, Trace 2 is showing our NEW PC-READY data.
(Thank's GI for providing your NO-SECURITY data authorization stream!)
 

Software on the PC side? Real cool. I quickly put together this "hack" tonight which supports 16550 uarts, COM 1 or 2. And allows you to vary the baud rate slightly.

The software looks like this:

The program strips all the junk off and provides you with formatted GI command strings!
You can use this program to read data off of your cable line, extra data from test chips and
cubes. The following is data collected from the Phantom cube:
 

Magicboxes - Jerrold Data Logger v0.1    -  Jim Borden   - 1998(c)
Unregistered version, contact us for other PC-type Jerrold Control software
Need custom test chips? Contact us!  http://www.magicboxes.com

 3 FD 6E 92 FF FF FF FF FF
11 FD 4D E0 80 76  0  B  0 2A  0  0  0  0  0  0  0 9A FF FF FF FF FF
 8 FD 49 E0 80 76  0  0 DC FF FF FF FF FF
FD 50 E0 80 76  0  0 D5 FF FF FF FF FF
E8 E0 80 76  0 FF 3C FF FF FF FF
 7 E9 E0 80 76  0 FF 3B FF FF FF FF
 7 EA E0 80 76  0 FF 3A FF FF FF FF
 7 EB E0 80 76  0 FF 39 FF FF FF FF
 7 EC E0 80 76  0 FF 38 FF FF FF FF
 7 ED E0 80 76  0 FF 37 FF FF FF FF
 7 EE E0 80 76  0 FF 36 FF FF FF FF
 7 EF E0 80 76  0 FF 35 FF FF FF FF
 7 F0 E0 80 76  0 FF 34 FF FF FF FF
 7 F1 E0 80 76  0 FF 33 FF FF FF FF
 7 F2 E0 80 76  0 FF 32 FF FF FF FF
 7 F3 E0 80 76  0 FF 31 FF FF FF FF
 7 F4 E0 80 76  0 FF 30 FF FF FF FF
 7 F5 E0 80 76  0 FF 2F FF FF FF FF
 7 F6 E0 80 76  0 FF 2E FF FF FF FF
 7 F7 E0 80 76  0 FF 2D FF FF FF FF
 9 FD B0 E8 E0 80 76  0 FF 8D FF FF FF FF
 9 FD B1 E9 E0 80 76  0 FF 8B FF FF FF FF
 9 FD B2 EA E0 80 76  0 FF 89 FF FF FF FF
 9 FD B3 EB E0 80 76  0 FF 87 FF FF FF FF
 9 FD B4 EC E0 80 76  0 FF 85 FF FF FF FF
 9 FD B5 ED E0 80 76  0 FF 83 FF FF FF FF
 9 FD B6 EE E0 80 76  0 FF 81 FF FF FF FF
 9 FD B7 EF E0 80 76  0 FF 7F FF FF FF FF
 9 FD B8 F0 E0 80 76  0 FF 7D FF FF FF FF
 9 FD B9 F1 E0 80 76  0 FF 7B FF FF FF FF
 9 FD BA F2 E0 80 76  0 FF 79 FF FF FF FF
 9 FD BB F3 E0 80 76  0 FF 77 FF FF FF FF
 9 FD BC F4 E0 80 76  0 FF 75 FF FF FF FF
 9 FD BD F5 E0 80 76  0 FF 73 FF FF FF FF
 9 FD BE F6 E0 80 76  0 FF 71 FF FF FF FF
 9 FD BF F7 E0 80 76  0 FF
 
 

    This project is now falling under the 3-chip non-profit project. The software below is free however if you want a registered version including "Packet"/"Command" identification code please donate $50 to the 3-chip project. For $75 we will send you a complete data logger with software.

    As we all know Steve Glendening's cable area uses CFT2200s and is not digital yet (and we all know he's been saying it will convert tomorrow).I hope this code will allow more people in HIS area to better understand the system and start testing ;-)

Programs to follow:
 

Jerrold Data Router
Actual dual-port IBM -PC Jerrold data router which will take all commands on the input and CHANGE them to HAPPY commands on the output. For instance, shutdown commands converted to turnon commands, etc...
 

Jerrold Data Bridge with programmable filters for problem areas
This program will allow you to experiment with their data until you find out what they are doing to be mean!

ESN Finder
This unit will poll your DPBB and CFT and report back to you the INTERNAL Subscriber number the cable company has put in your box.
 

Test Chips & Cubes
We will be putting online source code & schematics, PCB layouts and gerber files  to all the major cubes (Phantom, Cheetah, DR. Jerrold, RFT, T2, Stick, FSK) + manufacturing information so you can make your own for around $8-10 each in quantities of 500.
 

Check bad here regularily for updates. If you want test chips from us first, you can expect the best. Second, its custom for you!. We sell them at $8-12 each so we don't make a lot on them and if you are buying them from us we will make sure your set tops DON'T go down as we write code on the fly. We have test chips available for North America, UK, Europe, and most other countries.
 

Files
Download source code for the PIC16C54/XT-P
Download obj file for the PIC16C54/XT-P
Download MagicLog - the unregistered version.
 

KNOWN BUGS:
Hardware:   None, just use a GOOD 5V supply with filtering. No noisy packets!

PC Software: The queue cycles 150K right now so save after a few minutes. (Make sure you hit clear buffer before you save). The registered version stops after 300K and all registered folks will get the updated version with PacketIdent, and continuous logging. E-mail updates will be provided. This is now part of the 3-chip project and is therefore non-profit. Make lots of cubes and testchips!
 

P.S. Scientific Atlanta - haven't forgot you. A VBI data logger will be made available soon along with a packet logger for your older FSK datastream models).
 

1. Quick cloning of ESN numbers!
2. Can be used without the need of a cube!