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hyiger
hyiger

Reputation: 37

How to enable the JTAG pins on Altera MAX7000S devices

I bought a lot of Altera MAX7064S 48 pin QFP CPLDs (EPM7064STC44-10N) from eBay. Trying to access through the ISP JTAG pins and none of them show up on the JTAG chain, I'm getting no data back from TDO. For reference, I'm using a Terasic USB Blaster which a clone of the original Altera device. I have a simple rig setup with a socket and one I bought from a reputable source works fine. This leads me to believe that the chips I purchased were pulled off of boards and previously configured to permanently disable the JTAG so the pins could be reused for I/O.

As per AN 39: IEEE 1149.1 JTAG Boundary-Scan Testing I have TMS and TDI pulled to VCC and TCK pulled to GND

AN-39 Also states:

The IEEE Std. 1149.1 BST circuitry of MAX 7000S, MAX 7000A, MAX 7000B, and MAX 3000A devices is enabled by an IEEE Std. 1149.1 enable bit within the device. A blank device always has the BST circuitry enabled. The Altera MPU or a third-party programmer can set the state of this enable bit when programming the device. The state of the JTAG enable bit may not be changed using ISP via the IEEE Std. 1149.1 port.

So this seems to imply I need some sort of EEPROM or Microcontroller programmer to reset this bit? I googled around and found I would need a PLMT7000-44 adapter along with the Altera Master Programmer which is 20Y old equipment. I wonder if I could use a microcontroller and build a rig that can reset this bit? I can't seem to find any information on what voltages and timings and on what pins.

Upvotes: 0

Views: 1129

Answers (1)

hyiger
hyiger

Reputation: 37

The JTAG BST flag can be reset in Quartus II 13sp1 by creating a simple project like a 1-bit inverter and then programming the device with the corresponding bitstream. The problem is that it can't be done over JTAG ISP and must be done with an external programmer such as the Data I/O Labsite or Insite or an Altera PL-MPU. These programmers are very hard to find in working condition and expensive since they were discontinued at least 20 years ago.

There are some resources on the net that have these programmers and will reset the CPLD's for a small fee. One example is: Blue Feather Technologies

Upvotes: 0

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