http://dreamjam.co.uk/emuviews/pal/index.html
http://dreamjam.co.uk/emuviews/elec/pal.php

Introduction

This device recreates the logic equations (which can be compiled into a JEDEC fusemap) from read-protected PAL and GAL devices.

Project status

Revision 3 (pictured, leftmost) is currently in development. It supports 20-pin PALs. 24-pin PAL support is implemented in hardware but the software needs additional work to enable reading and analysis of those parts. It also has hardware to accomdate analysis of registered PALs, which is being developed. Consider this a work in progress.

Online documentation and tutorials are here.

Using the PAL Device Reader

(C) 2007-2008 Charles MacDonald

Disclaimer

Use the information presented within at your own risk. Some steps will involve modifying your operating system's settings, adding devices to your computer, and handling of electronic components.
Please take all proper precautions necessary.


Overview

You'll need to provide the following:

USB cable
"A"-type male connector to "B"-type male connector.

DC power supply
Only use a +9V DC regulated power supply, around 800mA. The power jack accepts a 2.1mm male connector, negative tip, positive sleeve.

This is identical to the power supply used in the Sega Master System.
I would recommend plugging it into a power strip with a switch so you can easily turn the PAL reader on and off.


Device Support

The PAL analysis hardware and software supports programmable logic devices, either PAL or GAL, that conform to the 16V8 pinout, that is:

Pins 1-9 are inputs.
Pins 11-19 are inputs, outputs or bidirectional.
Pin 10 is ground, pin 20 is 5.0V.
3.3V devices are NOT supported.
This includes devices such as:
10L4, 10L6, 10L8
12L4, 12L6, 12L8
16L4, 16L6, 16L8
16V8 (when not configured as registered)
18CV8 (when not configured as registered)
PAL types

Programmable logic devices primarily come in two types: combinatorial or registered. Only combinatorial devices are supported.

Any PAL with an "L" in its device name, such as PAL16L8, PALCE12L4, is combinatorial only.
Any PAL with an "R" in its device name, such as PAL16R8, PALCE12R4, is registered or partially registered/combinatorial. These are NOT supported
Any PAL with an "V" in its device name, such as GAL16V8 can be configured as combinatorial, registered, or partially combinatorial/registered. Only combinatorial configurations are supported
16V8 and 18CV8 devices are a superset of the PAL architecture and can be programmed to be combinatorial and/or registered. The analysis software will try to detect the attributes that a registered PAL would have, and warn you if it suspects the PAL is configured as registered.

One way to determine if a 16V8-type PAL is registered is to examine its connections on the PCB. All registered PALs use pin 1 exclusively as a clock input, and pin 11 exclusively as an active-low output enable. A common scenario for registered PALs is to have pin 11 tied to ground so the outputs are permanently enabled. Pin 1 may be tied to a nearby clock signal, though it isn't always easy to tell.

18CV8 devices, depending on how they are programmed, may not be detectable as being registered even when they are.

Replacements

You will be able to generate JEDEC files for GAL16V8 and GAL22V10 devices to function as replacements. Fuse maps for other devices are not supported.
Driver Installation

Uninstall old drivers

If you have an older FTDI driver installed, you may need to uninstall it.
Select "Add/Remove Programs" from the Control Panel, look for "FTDI USB Serial Converter Drivers", and choose "Change/Remove":

After it has been uninstalled, ensure no devices using FTDI chips are plugged in.
Then reboot your computer.

Install new drivers

Download the appropriate driver archive from FTDI's "D2XX Direct Driver" page:

http://www.ftdichip.com/Drivers/D2XX.htm
For example, if you are running Windows XP you'd want "CDM 2.04.06 WHQL Certified.zip" driver package.
Unzip the file to a directory, such as "C:\CDM 2.04.06 WHQL Certified\".
Take a look in the directory, there should be .INF and .CAT files present.
Connect the PAL analysis board to your PC and apply power.
The red LED on the PCB should light up.
Windows will recognize the FT2232 chip after a few seconds.
When prompted to install drivers, select the directory you unzipped them to and choose OK.
Windows should install the drivers and tell you that the device is now ready to use.

Hardware Overview

Turn the power OFF before removing or inserting PALs into the reader.

To remove a PAL that is in the socket, insert a small flat-head screwdriver underneath the chip and twist the handle gently to pry it up slightly.
The socket has a recession underneath the chip to facilitate this. Repeat the procedure on both ends until it is fully disengaged.
Always be very careful when removing or inserting PALs to prevent pins from being bent or damaged.
Make sure the PAL is inserted correctly or else it may be damaged when power is applied.
Double check that the orientation of the PAL is correct.

Revision 1 Hardware

NOTE: Supports 20-pin devices ONLY.
Insert the PAL with the pin 1 indicator (notch) facing towards the USB and DC power jack.
Revision 2 Hardware

NOTE: Supports 20-pin devices ONLY.
Insert the PAL with the pin 1 indicator (notch) facing towards the USB and DC power jack.
Revision 3 Hardware

Insert the PAL with the pin 1 indicator (notch) facing towards the DC power jack.
This also applies to 20-pin devices as well, they should be inserted at the rightmost side of the socket.

Indicator LEDs:
Red LED
Power supply indicator.
Lit when the PAL Device Reader is powered.
Green LED
PAL power supply indicator.
Lit when the PAL is being powered. This happens during a read operation.
Yellow LED
Fault indicator.
Brightly lit when there is a short circuit, like when a PAL is plugged in backwards. Turn off power immediately.
May flash briefly when power is turned on or off, this is normal.
Will be dimly lit or flicker during certain operations, this is normal.
The switch selects the type of PAL device you want to read.
The switch should be UP for 24-pin devices and DOWN for 20-pin devices.
Always ensure the switch is in the correct position before applying power.
Tutorial: Reading a PAL device

Open up a command prompt and go to the directory that contains the pd.exe program. Then apply power to the PAL reader.
Windows may take a few seconds to recognize the device, and during that time the application will report that there are no devices present.

When ready, type "pd dump <filename.bin>" and press Enter.

Now you have a binary dump of the PAL state. This is not a copy of its internal contents, but a collection of every possible output the PAL can generate for every possible given input.
The data needs to be analyzed to determine how the PAL was programmed.

Tutorial: Getting Started with WinCUPL

Overview

WinCUPL will be used to generate fusemaps for creating replacement PALs, and minimizing CUPL equations down to more manageable sizes.

Installing WinCUPL

Download and install Atmel's WinCUPL software:

http://www.atmel.com/dyn/products/tools_card.asp?tool_id=2759
The software is free, but you will have to register in order to download it.
Starting a new project

Launch WinCUPL by double clicking on the WinCUPL icon on the desktop.

Select "File -> New -> Design File"

Change the Name property to the name of your device.
For this example the PAL I am using is labeled "ROM1".

Use the default of zero input pins and choose "OK".

Use the default of zero output pins and choose "OK".

Use the default of zero pin nodes and choose "OK".

Erase the existing text in the edit window. Now we have our template for a PAL design created.
Note the path and filename shown in the edit window's title bar, this is where the output from this project will be written to.

Setting up options

Select Options > Compiler > Output Files tab.
Check the checkboxes as shown.

Select Options > Compiler > General tab.
Check the checkboxes as shown.
NOTE: Make sure "Secure Device" is not checked.

Select Options > Compiler > Minimization tab.

I would suggest Expresso and then Quine-McCluskey if that doesn't produce the kind of results needed.
Change the settings based on what device you are trying to fit the design into.

Change the settings based on what device you are trying to fit the design into.
Don't select "Keep XOR Equations".


Tutorial: PAL analysis

To analyze the contents of the data that was read, type "pd analyze <filename.bin>" and press Enter. The output will be written to stdout, so you may want to redirect it to a text file of the same name as the device. Use the PLD extension, this is the file extention for CUPL source code files.

You can open the file in a text editor to examine the results. Here is the sample output:



The PLD file contains a set of equations that represent the PAL logic and configuration in a format called CUPL. You can add "C"-style comments to the file, by prefixing a single line comment with // and enclosing a multi-line comment with /* ... */.

The equations are series of statements joined with '#'. Notice that pins B3-B7 have a one line equation each, and pin B0 is a multiple line equation. Some equations can have just one line, or several lines, or several thousand lines.

The CUPL file is the important part that describes how the PAL works. Fusemaps do not convey this information in a human-readable form, and they are tied to specific devices whereas CUPL presents the information in a more generic way. This also means the CUPL source can be used to fit the design that into other PALs or GALs if needed.

Documentation

You can and should document your work. Add comments to the file, including details such as:

Text from added markings or labels on the PAL ("SEGA 315-5220", "WH-02")
Manufacturer and part number (Lattice GAL16V8B, MMI PAL16L6BCN)
Device package (PDIP-20, CERDIP-20)
This information may not be present in the part manufacturer's part markings alone.
PCB the device came from, and its location. (Namco System 2 PCB, location 9K)
You can add comments ot a CUPL file, such as what is present at the top of the output. I would strongly advise adding your own notes, this will help other people working with the same hardware to understand what the CUPL source code corresponds to.

For example, this is how the above sample could be edited:



And don't just stop there. Now that you know how the PAL is configured, trace out the connections on the PCB. Write down the other components the PAL connects to. The PAL equations themselves are worthless without knowing how the PAL is connected to other hardware on the board. This is not the case with EPROMs and PROMs which sometimes are self-explanatory.

What Went Wrong?

You may have analyzed a PAL dump and seen a warning at the start of the output that is similar to the following:



This means that during analysis, the utility found that one or more bidirectional pins had the attributes that a registered PAL would have. While this should be taken as a strong indication that the PAL is configured for registered operation, if you know for a fact that it is not, then consider this warning to be incorrect.

The purpose of this warning is to help identify registered PALs which are unlabeled, or are similar to the 16V8 type which can be configured to be combinatorial or registered.


Tutorial: Minimizing equations

You should attempt to minimize any multi-line equation.
Here's the output from a PLD dump that is a candidate for minimization.



To minimize this equation, follow these steps:

Create a new project as shown in the WinCUPL tutorial.
Cut and paste the output from your PLD file into the editor window.
Select Run > Device Dependant Compiler or press F9.
It should compile with no errors.

Now open up the .SIM file which is in the same directory as the .PLD file, this directory is listed in the title of the editor window.
For example, if your PLD file is "ROM1.PLD", the SIM file is "ROM1.SIM".

Near the bottom of the file, there is a section enclosed in "%EQUATION" and "%END". Within this area are the minimized equations.
Here's one of them:



You should cut and paste this in place of the larger set of equations that are in your .PLD file, in this case replacing the set of equations for B0.
Notice that the syntax isn't quite right for CUPL; change "=>" to "=" and add a semicolon at the end of the last line:



Try compiling it again (F9). If there are no errors, you have successfully replaced the original set of equations with the minimized ones.

This wasn't much of a reduction, just three lines down to two. However it's possible to have output that has hundreds of thousands of lines, and those can often be minimized to just a few lines as well.

Some pointers:

Don't try to minimize the minimized results.
If an equation cannot be minimized, even if it's fairly large, that's normal. Not everything will reduce.

Tutorial: Creating a JEDEC fuse map

Create a new project as shown in the WinCUPL tutorial.

Cut and paste the output from your PLD file into the editor window.

Select Run > Device Dependant Compile (or press F9).
It should compile successfully with no errors.

Now we need to "fit" the PAL design into a target device. Typically any modern replacement of an older device will be with a GAL16V8, because it's reprogrammable, inexpensive, and functions as a superset of all previous PAL architectures.

The PLD file has a suggested device type, though the actual device is set to virtual:



Edit the "Device virtual;" line in the source code to replace 'virtual' with the suggested device type, or whatever other device you are intending to use. Atmel's documentation lists which devices are supported by WinCUPL.

Now try a device dependant compile again and see what happens (Run > Device Dependant Compile or F9).

If compilation is successful, you will now have a JEDEC fusemap with the same filename as your project's name with a .JED extension, located in the same directory as your project files. This directory is printed in the title of the source code pane of WinCUPL, and is 'c:\wincupl\wincupl\rom1.jed' in my example screenshots. The .JED file can be programmed directly to a GAL16V8 part.

Verifying the replacement

I would strongly recommend dumping the replacement PAL you made and compare the new dump to the original device dump. You can do this in DOS by typing:

fc /b oldfile.bin newfile.bin
It will tell you if the files are identical or not. If not, then your replacement is not working identically to the original device and something is wrong.
This is important as an imporoperly programmed PAL could damage the circuit it's plugged into. The PAL analysis board can handle any type of PAL programming so it will always be safe to read a PAL in it for verification.


Troubleshooting

"Error: No devices attached."

Check the following:

Ensure the DC power supply is plugged into an outlet, and the other end is plugged into the PAL analysis board.
Ensure the red power LED is lit when power is applied. If it isn't, check your power connections again.
Ensure the USB cable is connected between the PAL analysis board and your PC.
If you continue to get this error message, you will need to verify that Windows has recognized the device.
Download the USBView utility from this page:
http://www.ftdichip.com/Resources/Utilities.htm
Run USBView and look for an entry called "USB Composite Device" which has an idVendor field set to Future Technology Devices International Limited


If you can't find it listed, you should uninstall and reinstall the FTDI device driver.


Revision 3 Fix

This modification allows the PIC to inhibit switching until enumeration has completed. Please read all of the steps first before attemping the modification.

1.) Solder side: Cut the following trace going to pin 6 of the PIC chip socket. Use a multimeter to verify the connection has been severed.

2.) Solder side: Solder a wire between pin 16 of the 40-pin USB module socket and pin 6 of the 8-pin PIC socket.

3.) Component side: Remove resistor R2. We will reuse it in the next step, or you can simply get a new 4.7K ohm, 1/8 watt resistor to replace it.

4.) Solder side: Solder one lead of resistor R2 to the circled point.

5.) Solder side: Solder the other lead to any +5V point. This includes the area that is circled or anywhere along the vertical track that is boxed.

Be extra careful that the leads of the resistor do not touch anything else.
You could place electrical tape underneath the resistor or use heat shrink tubing or an insulating sleeve on the leads to keep them from touching other exposed tracks underneath it.

6.) Reprogram the PIC12F675 with the new firmware (main.hex):

pic-rev3a.zip
The current utility program (pd-rev3.exe) will work with the modified hardware.