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ADUC841 PSEN voltage level

Question asked by Oppie on Oct 18, 2011
Latest reply on Oct 27, 2011 by MMA

I have several ADuC841 devices that are on a common serial programming bus. This is used for field reprogramming of the device in a much larger system.

A host processor port is asseting the psen line low through a schottky diode and 1K resistor to each ADuC. All other devices are kept idle except the one being programmed. Works well but I wanted to confirm the voltage required on the PSEN pin to get the device to enter program mode. Would like to use a plain vanilla Si signal diode instead of a Schottky but need to determine the voltage margins. The diode serves to isolate the normally low state of psen from disturbing the other devices.