I had problem with FV-1 not reading the correct program from external eeprom. I tested the circuit by setting FV-1 to read from an external eeprom starting from program 1 to program 8 ( the eeprom contains 8 distinct programs), and here's the result :
Program Adress_|_Program read by FV-1
___ 000 ____________ Program #1______<-- OK
___ 001 ____________ Program #2______<-- OK
___ 010 ____________ Program #1______<-- WRONG ( should be Program #3 )
___ 011 ____________ Program #2______<-- WRONG ( should be Program #4 )
___ 100 ____________ Program #5______<-- OK
___ 101 ____________ Program #6______<-- OK
___ 110 ____________ Program #5______<-- WRONG ( should be Program #7 )
___ 111 ____________ Program #6______<-- WRONG ( should be Program #8 )
I check the voltage on FV-1's program address pins and they are correct. Looking at the result it seems that the 2nd address bit is always read as '0' by FV-1 internally, regardless of the actual voltage on the pin. I replaced the EEPROM just to be sure that it's not caused by faulty EEPROM, the same problem remains.
I only had this problem with the 6th board that I've built. Am I having a faulty FV-1 chip?
External EEPROM read problem
Moderator: frank
I've never seen that error before. The chips are all tested and run through 8 external programs to check loading, etc. I would carefully check for a solder bridge possibly under the chip or other reason why the chip thinks the pin is low.
Frank Thomson
Experimental Noize
Experimental Noize
Glad you found it, those intermittent ones can be a real pain to find.
Frank Thomson
Experimental Noize
Experimental Noize