68332 Bus arbitration with flash parts
2002-05-04 by tenakbritt
We have seen rare instances in our application when on a read of a flash memory part the part outputs 0xffff. The part is not corrupt, a subsequent read will produce the correct data. We have caught several of the incidents on a logic analyzer and have found that they always occur after a bus arbitration cycle. The 68332 tri-states the address lines, the pull-ups start to pull them up, then the address lines are driven with a valid address and the flash is read. The flash is used with the chip select always pulled, and WE and OE are toggled. Does anyone know of a problem with flash when the CS is pulled and WE and OE are disabled, if the address lines are at invalid levels? Also, is there a way to minimize the time between when the 68332 stops driving the address lines, and when it issues a bus grant? (BG)