I have a question about a fault finding technique I learned sometime last century … about making a micro run continuous “nop” instructions (using 8085 and Z80 etc).
I have a board that uses a separate micro, SRAM and a flash memory chip - that I’m trying to fault find.
Have replaced the flash chip and SRAM to no avail … yet that chip works fine on another board.
(The board displays the same symptons I see when it has a crook flash ... but in this case, a new flash didn't solve it)
At the moment, all I can recall to do is to check DC levels, clock signals … then what?
I’d often thought about using the nop technique but never did because of the effort needed to remove and swap around large smd chips. Now that I have a decent hot air desoldering tool … it feels more doable.
The micro is a H8S/2350. How hard (or worthwhile) would it be to write a routine to load on flash and check the result?
... and if worthwhile ... how does one go about doing that.
Thanks for any help.
I have a board that uses a separate micro, SRAM and a flash memory chip - that I’m trying to fault find.
Have replaced the flash chip and SRAM to no avail … yet that chip works fine on another board.
(The board displays the same symptons I see when it has a crook flash ... but in this case, a new flash didn't solve it)
At the moment, all I can recall to do is to check DC levels, clock signals … then what?
I’d often thought about using the nop technique but never did because of the effort needed to remove and swap around large smd chips. Now that I have a decent hot air desoldering tool … it feels more doable.
The micro is a H8S/2350. How hard (or worthwhile) would it be to write a routine to load on flash and check the result?
... and if worthwhile ... how does one go about doing that.
Thanks for any help.
