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Using PAL/GAL as 74C926 IC

 
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killex



Joined: 13 Sep 2003
Posts: 17
Post06 Oct 2003 12:10   Using PAL/GAL as 74C926 IC
Hi. I wonder if it is possible to program a PAL or GAL to "build" a 74C926 (4-digit counter with multiplexed 7-segment output drivers) and if it' s possible if anyone have the code to program this (and the PAL/GAL marking). This is because the74C926 is very expensive and I have some PAL ready to use.
Thanks.

PS: Sorry me if I said a stupid thing but I never used programming logic devices.
Bye
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sc/mp



Joined: 10 Feb 2002
Posts: 142
Helped: 1
Post06 Oct 2003 13:49   Re: Using PAL/GAL as 74C926 IC
With 4 digit counter and a 7segment driver your design needs 23 macrocells (4x4 +7) ....more if you want the latches between counters and driver.

So you can't fit it into a single PAL or GAL (10 macrocells)l

A small CPLD (64 macrocells, maybe 32) from @ltera, Xilinx, Lattice..... should handle your design.

Regards
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killex



Joined: 13 Sep 2003
Posts: 17
Post06 Oct 2003 16:58   Re: Using PAL/GAL as 74C926 IC
Hi.
Do you know where to find a good guide (with examples) to know and to program PLD, GAL, PAL ?
I never used them so I don't know what are macrocells... I only know that this PLD can be used to create a logic net burning "microswitches" on their inside.
The IC (74C926) I'm looking for has 7 output lines (a to f) to pilote 7-segment displays and 4 output lines multiplexed (so these scans 4 displays connected in parallel scanning their cathodes).
The pins are:
7 output (a-f) for the 7 segments of the displays
4 multiplexed output for the scanning
1 latch enable
1 display select
1 clock
1 reset
1 carry out
I attach the datasheet, if you want to look at it.
Thanx

Sorry, but you need login in to view this attachment
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sc/mp



Joined: 10 Feb 2002
Posts: 142
Helped: 1
Post06 Oct 2003 17:37   Re: Using PAL/GAL as 74C926 IC
Hi !

here is a good starting point :

http://www.optimagic.com/faq.html (look for SPLD and CPLD)
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