README.md

PHPPLD

PHPPLD provides a simple and easy way to use EEPROMs as a programmable logic device.

The behaviour of the resulting bitstream can be described as a simple PHP script.
Logical functions like NOT, AND, OR, XOR, etc. as well as more complex address decoding can be done. There is also an example script for generating a 800x600 VGA output. (100x600 effective resolution)

Examples

// NOT gate
$output[0] = !$input[0];

// AND gate
$output[1] = $input[1] && $input[2];

results in:

Input 000 - Output 0000 0001
Input 001 - Output 0000 0001
Input 010 - Output 0000 0001
Input 011 - Output 0000 0011
Input 100 - Output 0000 0000
Input 101 - Output 0000 0000
Input 110 - Output 0000 0000
Input 111 - Output 0000 0010

Another example:

$address = integer_value($input);

if ($address >= 0x20 && $address <= 0x40)
{
	$cs_soundchip = 1; 
}
if ($address >= 0x60 && $address <= 0x65)
{
	$cs_videochip = 1; 
}

$output[0] = $cs_soundchip; 
$output[1] = !$cs_videochip; // Note the inversion for active-low signals

Usage

php phppld.php -i 17 -w output.bin examples/logic.php
generates a bitstream for an EEPROM with 17 address pins [A16:A0] (128 KiB).

php phppld.php -i 17 -t 0x30 examples/logic.php
shows the result for input 0x30 (decimal values are also accepted).

Security notice

Input files to PHPPLD are PHP source code files which will get executed!
They can have any kind of malicious content and do everything a normal PHP script can do.
Keep this in mind when evaluating third-party PHPPLD files.