AVR with FPGA

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npat_avr
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Posted by npat_avr: Sun. Dec 6, 2009 - 04:17 PM
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Hi Freaks,

I am an FPGA newbie and want to interface a M328P AVR with an A40MX02 FPGA.

The FPGA is already programmed and I would like to check if it is functionally working. I did not see any on board EEPROM to read back memory contents. What would be the best way to test functionality? Would using the JTAG pins ensure a good test? I also saw it has the SDI, SDO, SCLK pins. Can I use these with the MISO, MOSI, SCK pins on my AVR? I already have a board with these pins mapped out so it would be easy for me if I can check for FPGA functionality with these pins.

Thanks.

Attachment(s): 

PDF icon FPGA datasheet

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AVR Microcontrollers, megaAVR and tinyAVR
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leon_heller
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Posted by leon_heller: Sun. Dec 6, 2009 - 04:27 PM
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If you have the original FPGA code you could reprogram it with a simple test program. You will need the Actel software and a programming interface, of course.

Leon Heller G1HSM

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npat_avr
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Posted by npat_avr: Sun. Dec 6, 2009 - 06:04 PM
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Can I not use the AVR JTAG and/or AVR SPI pins to check if it is working?

I can't write to the FPGA as it is protected. I just want to read back or check if the i/p and o/p are working.

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leon_heller
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Posted by leon_heller: Sun. Dec 6, 2009 - 08:38 PM
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In theory you could use the AVR JTAG with your own software with the FPGA, or program the AVR to interface it to the Actel JTAG. It would be a *lot* of work.

If the FPGA is protected you probably won't get much more out of it than the ID.

If you have the FPGA input and output details you could test it by supplying it with appropriate signals and checking the outputs with a scope or logic analyser.

Leon Heller G1HSM

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npat_avr
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Posted by npat_avr: Mon. Dec 7, 2009 - 12:56 AM
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Can I apply logic level signals through an AVR and read the outputs from the o/p pins with an ADC? I could probably MUX the FPGA output pins and read them with an ADC. If I know the expected output (1 or 0) from a particular group of FPGA pins, maybe I can read it into an AVR and compare it with a LUT?

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leon_heller
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Posted by leon_heller: Mon. Dec 7, 2009 - 11:41 AM
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Why read them with an ADC? They are digital signals, just use AVR inputs.

Why do you need to do this, anyway?

Leon Heller G1HSM

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