Open Access
Programming the MACH and PAL Devices
10-2
ARM Development Board (ARM7TDMI Version)
Hardware Reference Guide
ARM DUI 0017C
10.1 Reprogramming a Device
Much of the programmable logic on the ARM Development Board is implemented in AMD
MACH and PALCE type devices. These devices are based on electrically erasable (EE)
technology so they can be reprogrammed to add or change functionality if required.
This should only be attempted if you have a full and detailed understanding of the design.
There are many and varied reasons why you might want to make modifications.
For example:
• One reason why you might want to do this is to change the address map. In this
case, you program the decoder.
• Alternatively, you might want to change the priority of bus masters, in which case
you alter the arbiter.
• If you want to fit slower SRAM, you need to modify the SRAM controller to prevent
unsuitable switch positions crashing the system.
ARM can assist with making such modifications. See
Appendix C, Summary of
Programmable Devices
for information on all the PLD filenames and how to obtain them
from ARM.
10.1.1 Design files
Reprogramming a MACH or PALCE device on the ARM Development Board requires
a design file. This design file comprises a list of logic equations in a hardware description
language (HDL). Various tools are available for this, such as:
ABEL from Data I/O
PLDesigner from Minc
PALASM from AMD
All the designs for the ARM Development Board were completed using PALASM which is a
low-cost proprietary tool from the device vendor AMD.
If you use a different PLD design tool then it should not be too difficult to modify the PALASM
description to suit your front end. No special constructs have been used, so the process
should be straightforward.
10.1.2 Preparing a .JED File and Programming a Device
A tool such as PALASM turns a design written in an HDL into a fuse map. This fuse map is
described in a JEDEC standard file format. The file, usually called
filename
.jed, can be
downloaded into the target device using a logic programmer.
hrg.book Page 2 Wednesday, July 22, 1998 9:18 AM
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