New Project.pdf

thinking this should work ok , was concerned about the sink current of the LEDs in the matrix , but if only 1 colum of led is on at any time then max sink current is 20ma per pin

thinking ratio of 1 key scan to 3 outputs of the led on signals , so that the keys are scaned every 150ms

the power switch was kept seperate input to ground so that is could trigger the Low going interupt for sleep mode wakeup