[aprssig] Re: Dual Configurations in EPROM

[Ed L. Locklear, KF4CHG]

WA8LMF2 at aol.com wrote:
> mcheavens at usa.net 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.
> 
> 
> 
> Many utilities that come with eprom programmers can do this quite easily.
> 
> 1)   Most programming apps read the data for the prom being programmed into 
> RAM  before blowing the eprom.  Set the programming utility to program a 
> 27C512.  This assigns a RAM buffer the size of a 27512.  You read the first 
> 27256-sized file into RAM and tell the programming utility to load it at offset 0000 
> Hex (the start of the first half of the RAM buffer) .  Then read in the second 
> 27256-sized file and tell the utility to load it at offset 8000 Hex (the 
> beginning of the the upper half of the RAM buffer).  This will stack the the two 
> eprom images into the lower and upper halves of a 27512-sized buffer 
> respectively.   Then blow the entire prom in one pass.
> 
> --- or ---
> 
> 2)  Some eprom apps allow you to program only part of an eprom at a time if 
> you want.  If you have this kind of programming utility, read the first file 
> and tell the programmer to blow 8000 H bytes starting at 0000 H.     Then tell 
> the programmer to read the second file and blow 8000 H bytes starting at offset 
> 8000.   
>      Or it may be expressed as start and end addresses instead of start 
> address and length. In this case, tell the programmer to program the first file 
> between 0000 H and 7FFF H, and to then program  the second file between 8000 H 
> and FFFF H.
> 
> --- or ---
> 
> 3) Combine the two image files into a single larger one.  This can be done 
> either by opening the files in a hex editor (or even Wordpad if you are 
> careful).  Select all of the file open in one instance of the editor, copy it and 
> paste it at the very beginning (or end) of the second file. Then save it   Or you 
> can use the classic DOS copy  command:
> 
>     COPY  /b    Filename1.bin+Filename2.bin    Filename3.bin   
> 
> where Filename1.bin  and Filename2.bin are the original UI-DIGI file and the 
> original TNC prom file while Filename3.bin is the combined file that I usually 
> name DoubleDecker.bin .   This command will combine ("concatinate") two or 
> more files into a single larger file.    Then just blow a single pass using a 
> 27512-sized file directly into a 27C512 with no offsets or segmenting required.
> 
> Once you have the 27512 eprom ready to install, bend pin  one so it misses 
> the socket when the prom is inserted into the socket.  Connect pin 1 to a 
> single-pole double-throw toggle switch so that you can either ground pin 1 or apply 
> 5 VDC  to it.    I usually use an E-Z-Hook micro-grabber  test lead to snag 
> the pin (instead of soldering to it) so I can easily remove the chip when needed.
> 
> 
> 
> 
> Stephen H. Smith             wa8lmf (at) aol.com
>                                                    
> Home Page:                   http://wa8lmf.com
> 
> New APRS Symbol Chart
>   http://webs.lanset.com/wa8lmf/miscinfo/APRS_Symbol_Chart.pdf  
> 
> New/Updated "Rev G" APRS     http://webs.lanset.com/wa8lmf/aprs
> Symbols Set for UI-View,
> UIpoint and APRSplus:
> 

Stephen,

Thanks for clarifing the SPDT switch.  In my first post I stated using a 
SPST switch, which is incorrect.

Ed, KF4CHG