How can I erase an Altera® device in-system using the JTAG pins?

It is possible to erase a configuration device or MAX^® device that supports in-system programmability (ISP) by using the Jam^TM Player and performing the following steps:

1. Create a Jam File (.jam) or Jam Byte-Code File (.jbc) for the targeted device using the Create JAM or SVF file option in the MAX PLUS^® II Programmer.

   You can use any Programmer Object File (.pof) targeted for the device to create the Jam File or JBC File.

2. At the DOS prompt, type the following command: jam -dDO_ERASE=1 <filename>.jam

   You need to have the Jam Player installed on your PC or in your embedded processor for the jam.exe executable to be recognized.

3. To ensure that the device was successfully erased, perform a blank check by typing the following command at the DOS prompt:

jam -dDO_BLANKCHECK=1 <filename>.jam

You can also erase any MAX device that supports ISP, by reading back the POF from a factory-shipped blank device and re-program the device with this POF. To read the blank POF from a factory-shipped MAX device, you need to "Examine" the factory shipped device by going into the Programmer in the MAX PLUS II software. This examined file can now be saved and used to re-program the already programmed device to factory default settings. Also, re-programming an already programmed MAX device with this factory shipped blank POF will tri-state all the I/Os after power up.

This process will work for an configuration device as well, but the device will not pass a blank check.

For all FLEX^® and APEX^TM devices, removal of power or driving nCONFIG low for 2 microseconds. automatically erases the device as all the FLEX and APEX devices are made using an SRAM process. Thus, the erasure of any FLEX or APEX device via JTAG is irrelevant.

Configuration and MAX devices are made using a FLASH and EEPROM process respectively, thus retaining their programming after the power supply has been disconnected to the device.