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CHess4's avatar
CHess4
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7 years ago

Getting started resources for MAX 7000

Hi, I am starting to develop with CPLDs, and​ when looking for basic MAX 7000 circuits, I don't find anything on the net. Is there a sample basic circuit for integrating a MAX 7000A into a schematic...
  • CHess4's avatar
    CHess4
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    7 years ago
    Hi, thank you, there are no schematics in that document. Where can I find sample schematics with power supply and in circuit programmability, ideally by a microcontroller?
    • ak6dn's avatar
      ak6dn
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      7 years ago

      Well the datasheet has all the info you need. It lists the VCC and GND pins and the VCC power supply requirements (ie, 3.3V +/- 10%). Programming is via JTAG pins TCK, TMS, TDI, TDO which would connect to GPIO pins on a microcontroller and/or a connector for use with an Altera ByteBlaster programming adapter. All the other I/Os are 5V tolerant and connect to whatever devices you want. I don't know what else a schematic could show you?

    • CHess4's avatar
      CHess4
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      7 years ago
      Then I guess it is easier than I thought… I am integrating it into a PCB without being able to test it on a breadboard first. Still, it is redundant to the 74xx logic I have on the board already, so it is not a catastrophy if it doesn’t work in the next PCB version. If I’m using it for combinatorial mode, I don’t need an oscillator, right, and apart from the decoupling caps (0.1µF) I just need standard protection for IO and take care about fanout and current limits I guess. Is there a way to have 5V output with 7000A? I am using 3V3 mostly but have WS2812b LEDs that need 5V for data. Until now I’m using a level shifter (74LS245). Do I need to connect JTAG to an UART / SPI / I2C port of my µC (STM32) or will any GPIO ports do? Thanks for your help
    • ak6dn's avatar
      ak6dn
      Icon for Regular Contributor rankRegular Contributor
      7 years ago

      If you are not using any clocked FFs then you don't need a clock source and can operate purely combinatorial logic.

      For sure you need to understand the max current drive limits for the I/Os. Datasheet will tell you the limits.

      The 7000A series is 3.3V supply and I/O voltage, but the I/Os are 5V tolerant. So you can add a pullup to +5V tied to an output if need be.

      JTAG is its own protocol (NOT the same as UART/SPI/I2C). So unless you have a JTAG knowledgeable master (like an Altera ByteBlaster) you will have to connect the JTAG pins to standard I/O ports on your micro, and then write the code that simulates the JTAG protocol. Be aware however that writing the code on a micro that does low level JTAG (ie, bit banging TCK/TMS/TDI/TDO correctly) is just a very small part of the problem. Writing all the code that implements full device programming thru JTAG is a whole other significant project. Old Altera used to supply source code for such a function (the old JAM STAPL player) but I don't know if that is still around now that Intel has assumed control.

      Personally I would recommend getting an Altera USB Blaster clone (Terasic has a nice one that is 100% Altera compatible that is inexpensive).