[aprssig] Dual Configurations in EPROM

Ed L. Locklear, KF4CHG kf4chg at earthlink.net
Mon May 23 08:04:47 EDT 2005

Mark Cheavens wrote:
> I am looking for a utility or how-to for loading two configurations. 
> (KISS mode and Ui-Digi) into a single 27C512 and use the hi/lo pin 1 
> configuration switch.
> I am tired of switching and having to keep multiple roms at sites for 
> testing.
> Thanks,
> Mark Cheavens


There is no real utility for making a dual configuration as such.  It 
depends on how you load in your hex or bin files into the programming 
software you use to burn EPROM's or PROM's (OTP one time program).

I use Prog-Studio from Batronix 

The following pertains only to the MFJ-1270B/C TNC's that I use here. 
All other TNC's may require different programming or stacking (EPROM's 
on top one another).

First you'll want to decide which mode you want to run as the default. 
Say it is UIDIGI, this would be loaded into the second bank starting at 
08000 and MFJ would be loaded into address 00000.

You'll want to read the MFJ EPROM (assuming this is what your using?) 
first, then save it as a .bin file.

Make sure the MFJ is loaded starting at 00000 and should end at 07FF7.
Then you can load in the UIDIGI.bin or whatever name you've saved it as 
and load that into address starting at 08000.  If you use Prog-Studio, 
you would do a Data Import and tell it to start at 8000h.

Burn the EPROM then install into TNC.  When you turn on the TNC it will 
default to UIDIGI.  Now to bank switch between the 2 addresses will 
require that you bend out pin 1 of the EPROM or use a 28 pin socket.  If 
you use the socket pin 1 of the EPROM need not be bent out, only the 
socket.  Here you will solder a piece of wire (wire wrap works good) 
long enough to wherever the switch will be mounted.

Use a SPST switch, from the EPROM pin 1 solder to switch, run another 
length of wire from switch to GND.  This will pull the different banks 
HIGH or LOW.  Be sure TNC is off when switching between banks.

Now here is the KICKER, if you have joined the UIDIGI Yahoo Group and 
have read the how-to setup UIDIGI in a MFJ-1270.  You'll have noticed 
the jumpers on the board have either been removed from one location and 
installed to another jumper location and a chip removal at U40.  All the 
above will be of no use for bank switching.  You will have to install 
others switches to turn off/on U40, make the other jumpers switch back 
and forth from MFJ or UIDIGI.  Maybe you could find a TPTT (triple pole 
triple through) switch some where or just use your imagination on how 
many switches you will need.


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