PIC/EEPROM JDM RS232 programmer

Introduction

Every engineer working with microcontrollers at some stage needs a programmer to download the code into their MCU. This programmer was developed, to prove a cost effective alternative to purchasing a commerial programming tool costing several hundred dollars. By using the standard JDM RS232 bit bashed interface the hardware is simplified and requires just a MAX232 RS232 level converter and a corresponding 4069 hex inverter to invert the logic inversion that occurs from the MAX232.

The power supply on the board is taken care of using a standard LM78L05 +5V regulator and the Vpp of 13V supplied to the MCLR pin is simply supplied as a pass though therefore be sure to make sure a regulated PSU (13V DC) is used to power this board.

The software to run this programmer is freely downloadable from the IC-Prog website. A futher advantage of using this software is not only are PIC MCU’s supported by standard off the shelf 93CXX, 24CXX and 25XX devices are also supported.

The download file includes 4 boards the main programmer board can be assembled easily and includes a combination of through hole and SMD the component overlay has the values to place onto the board.

The header pinout for the JDM interface is indicated on the silkscreen layer, and connected to the corresponding daughter board via a 6 way ribbon connector with is straight pin-pin connection.

When using the IC prog software be sure to use a hardware PC UART instead of a more modern USB-R232 com port adaptor if at all possible. These tend to create serious lag and can also create errors due to the non standard timing used by IC prog which preforms low level PC UART register access.

How to use

To setup hardware for use of PC, press F3 and set options as per above. On a windows 2000/XP system ensure that icprog.sys is located in the same directory as the program executable.

Images

All PCB’s including the socket boards are single layer, only a few passive SMD parts are used on the under side of the socket boards. Again on the main programmer PCB only a few passives and a couple of SOT23 transistors are placed on the underside.

Downloads

Schematic

Top PCB overlay

Bottom PCB overlay

PCB bottom layer

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