Hi,
I have two 08's that have been working normally, accepting programming etc.
They both have now ceased accepting the "in circuit" programming signal.
I did the serial port check and found that the pin2 voltage was only varying from -0.55 to 1.57V.
The voltage from the laptop is -5.33 to 3.25V.
I've had a closeup look a the board, but can't see/measure anything that may cause a problem.
A new 08 chip in the same socket works OK. (so far)
It seems that something in the faulty ones on Pin2 is now pulling the voltage down - there should be little voltage drop.
Has anyone experienced this problem?
I'm just glad it wasn't one of the bigger (more expensive ) chips.
The board has a 7805 regulator, fully bypassed, and there is minimal ripple on the supply.
I tried the faulty chips on my normal protoyping board - same result!
kenmac
I have two 08's that have been working normally, accepting programming etc.
They both have now ceased accepting the "in circuit" programming signal.
I did the serial port check and found that the pin2 voltage was only varying from -0.55 to 1.57V.
The voltage from the laptop is -5.33 to 3.25V.
I've had a closeup look a the board, but can't see/measure anything that may cause a problem.
A new 08 chip in the same socket works OK. (so far)
It seems that something in the faulty ones on Pin2 is now pulling the voltage down - there should be little voltage drop.
Has anyone experienced this problem?
I'm just glad it wasn't one of the bigger (more expensive ) chips.
The board has a 7805 regulator, fully bypassed, and there is minimal ripple on the supply.
I tried the faulty chips on my normal protoyping board - same result!
kenmac