The EPROMer5 is a legacy parallel-port (LPT) based device programmer. While modern USB programmers have largely superseded it, the EPROMer5 remains a functional tool for programming 27C256 and AT29C256 chips.

1. Chip Support#

The EPROMer5 supports the following memory ICs:

• 27C256: Natively supports standard 32 KB EPROMs (e.g., AMD, TI, or Intel 27C256).
• AT29C256: Supports Atmel electrically erasable EEPROMs via software revisions.

2. Troubleshooting and Configuration#

Due to the reliance on legacy parallel port communication and DIY assembly, users may encounter initialization or verification errors.

Solder Joint Verification#

If the device fails to identify chips or reports verification errors, inspect the PCB:

• Visual Inspection: Use magnification to inspect all surface-mount device (SMD) IC solder joints.
• Reflow: Reheat suspicious joints using a fine chisel tip and fresh flux to ensure electrical continuity.

Parallel Port Timing#

Parallel port communication is sensitive to host CPU clock speeds and bus latency.

Tip

When using older hardware (e.g., 600 MHz laptops), manually adjust the write timing in the programmer software. Setting the burn speed delay to 13 or higher is recommended to prevent data buffer overflow errors when writing to UV EPROMs.

Note

Flash memory, such as the Atmel 29C256, utilizes internal page buffers and is generally less sensitive to parallel port timing variations than standard 27C256 EPROMs.