USB/RS-232 Programmer for DCC decoders


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Support Page for Version 3 and Version 4 SPROG

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July 2006 Note

Version 3.9 firmware now available - see below.

V4 Downloads

User Guide and Assembly Instructions (PDF 143kbytes)
Firmware Guide (PDF 29kbytes)
Schematics (PDF 273kbytes)
Bottom side component placements (PDF 18kbytes)
Top side component placements (PDF 22kbytes)
Bill of Materials (.xls 21kbytes)

V3 Downloads

User Guide and Assembly Instructions (PDF 404kbytes)
Schematics (PDF 363kbytes)
PCB layout (PDF 146kbytes)
Bottom side component placements (PDF 56kbytes)
Top side component placements (PDF 82kbytes)
Bill of Materials (Excel 21kbytes)

PIC Programming - version 3.9

PIC source code is in Microchip ASM format.
PIC hex programming file

Software Requirements

For best results with SPROG you need DecoderPro

For the USB version you also need to download the FT232 VCP drivers from here

Firmware Upgrades

Unfortunately, the upgrade procedure seems to cause problems for some people and there seems to be a problem with Windows not always setting up the serial port correctly for hardware handshake. My own PC which always used to be reliable no longer works correctly with hardware handshake except for the USB version or using a serial version through a USB serial adapter.

DecoderPro version 1.5.7 and later includes a utility to upgrade SPROG v3/v4 firmware but, for the reasons mentioned in the prvious paragraph, I cannot recommend you use this at the moment. Please note that the code to do this in DecoderPro was written by myself and I take full responsibility. This problem does not affect in any way the otherwise excellent quality and functionality of DecoderPro.

You first need to download sprog3_8.hex.

Next download a copy of TeraTerm Pro from here

Configure TeraTerm Pro to connect to the COM port to which your SPROG is connected. Choose "setup|serial port" froom the menu and select 9600baud, 8 bit, no parity, 1 stop bit no flow control. Set the transmit delays to 1msec/char and 20msec/line. Reset SPROG whilst holding down the boot switch and you should see the "L>" prompt. Use "file|send file" to download the .hex file to SPROG. Once the transfer is complete, SPROG should restart automatically with the new version:

SPROG Ver 3.8
P> P>

If SPROG does not restart then use the reset switch and you should see the prompt.

Once you start the bootloader (the program within SPROG that allows you to install new firmware) you should always download a new firmware image. Resetting SPROG will just put you back in the bootloader. If you wish to get back to normal operation without downloading a new firmware image then carefully type the following (with SPROG connected to Hyperterminal, or similar, without the quotes) ":00000001FF". This should return SPROG to normal operation.

If your SPROG should lock up during the transfer of the hex file then I apologise and will fix any SPROG sent back to me free of charge.

If you have access to a PIC programmer (or ICD or similar) then it is also possible to re-program the PIC with the new firmware by connecting the programmer to J1 (see schematics for pinout) and using high voltage programming mode. Doing this will also update the bootloader with fixes for the problems mentioned above. I assume anyone with a PIC programmer will know what they are doing at this point, but please don't hesitate to contact me if you require further details.

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(C) Copyright 2005 Andrew Crosland