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How to use the PLA on the ADuC702x parts

Question asked by MMA Employee on Oct 1, 2010
Latest reply on Jan 7, 2011 by Dan.King

The ADuC702x family of products have a integrated PLA - Programmable Logic Array (16 Elements)

 

This is briefly explained in the Document "Precision Analog Microcontroller Overview Brochure" page 3 to think about as a Glue Logic replacement on-chip. It can be configured with the easy to use graphical PLA-Tool - as explained in "Easy way to configure PLA on ADuC702x".


The basic intention was, to have Inverters or other logical gates and/or Flip-Flip's available for Interrupt-Signal manipulation & creation. I.e. the first products in the Precision Analog Microcontroller family didn't have edge triggered external Interrupt-Inputs, so the PLA has been used as the solution for that.

 

Other ideas has been coming up soon - using the PLA as a sync-input-shift-register (up to 16 bits) or a sync counter for up to 8 Bits. Also it has been used to sync a SPI with a I2S audio bus.

 

Here a example for a 3-bit sync counter (only 4 Elements) on a ADuC7023 - the counter can be read out from PLADOUT MMR - no outputs connected. A GPIO (P0.5) is used as Clock-/Counter-input - Element 13,14 & 15 represent the 3 Counter bits and Element 12 is used for additional counter logic (PLA-file and C-Code for init attached)

untitled.bmp

Output with a small SW-loop on GPIOs shows the correct function - the shift between GPIO P0.5 edges and the bit signals is related to the time the SW-loop needs to execute.

Counter_small_text.bmp

My questions :

- Who has used the PLA in his application ?

- What was the application ?

- Please post more details about your application.

- What is your wish for future products ?

 

Thanks in advance!

 

MMA

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