Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

Unable to scan device chain

Hi all, I´m relativ new with the CPLD´s, and now I have the first problem with programming the device. It´s a EPM570T100. I ´m using a Elcamino PICoMax to programm the device. This works with on...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

Good diagnosis

I've also had problems with ground loops and laptops. Some (perhaps older) laptops have 2-pin mains adapter connections, which means there is no earth. So a substantial AC leakage current can run round the JTAG circuit ground if the DUT is properly grounded. There are at least two ways to fix this: 1 get an AC adapter with a properly connected ground; run a substantial ground cable from the parallel port to the DUT's ground.