Forum Discussion
Honored ContributorError:Cant access JTAG chain..help!
When i try to program the cpld i get this error
error: can't access jtag chain
error: operation failed. I am using a MAX2 CPLD.I would be able to program it a few months ago with no problem but now it suddenly gives me that error.Can anyone help??:confused: ps. I am using the usb blaster.
8 Replies
Altera_ForumNo original Altera or Terasic USB Blaster is sourcing a supply voltage to a device, cause it's designed to support a variable logic supply of 1.8 to 5.0 V. The only explanation is, that you had a user modified exemplar. MAX II, by the way, has a maximum supply and logic input voltage of 3.3 V, there are only some older EPM7xxx MAX devices working with 5V supply.
- Altera_Forum
Its working now!I mistakenly connected a 3v source to the 5v pin of the CPLD and when i moved it to its proper 3v pin it worked and i am now able to program it again.I do however remember programming it without connecting any voltage source to it just the usb cable to the computer, so that seems odd.Anyway thanks for all your help!!..im gonna go smoke a fat joint now.
- Altera_Forum
There is a JTAG debug option in Quartus Programmer, it can be used to trace the JTAG signals down to the device pins, checking for any broken connection.
- Altera_Forum
i powered and grounded the board but still get the same error.Is there a chance the board is broken?..I connected the cpld directly to my computer without using the usb cable so the cable doesnt seem to be the problem.
- Altera_Forum
You will need to power the board before you can program it.
- Altera_Forum--- Quote Start --- --- Quote Start --- Also when i click on Auto detect I get "unable to scan device chain.Cant scan JTAG chain"[/QUOTE Did somebody use the board last months ? Check all power supplies on the board ! It is also possible that your USB-Blaster cable is broken ! Can you replace your USB-Blaster for test ? Kind regards GPK --- Quote End --- Its been in storage since it last worked.Do i have to power the CPLD to be able to program it?..I think i remember programming it just with the cpld connected to the computer via the usb cable.
- Altera_Forum--- Quote Start --- Also when i click on Auto detect I get "unable to scan device chain.Cant scan JTAG chain"[/QUOTE Did somebody use the board last months ? Check all power supplies on the board ! It is also possible that your USB-Blaster cable is broken ! Can you replace your USB-Blaster for test ? Kind regards GPK
- Altera_Forum
Also when i click on Auto detect I get "unable to scan device chain.Cant scan JTAG chain"
