March 1999, Issue 104

JTAG—Working with CoolPLD

ISP PROGRAMMING

The XPLA ISP PC programmer software enables you to bulk erase, blank check, program, verify, read device IDs, secure devices, program, and read the user signature register.

The JTAG download cable (which comes with the ISP programmer) connects from the ISP’s JTAG port to any parallel printer port on your PC.

Because JTAG devices are designed to be daisy chained, if each device’s jedec file doesn’t know where its device is on the daisy chain, you have a problem. Issuing commands and having them go at the appropriate device becomes a nightmare. You must remember the state of each device in the chain and how many clocks it takes data to shift into and out of each device.

Fortunately, the ISP JTAG chaining software enables you to identify each device along with its jedec file. When you perform functions on specific devices in the chain, the software keeps track of the state of each device.