Maxim Integrated MAXQ Family Users Guide: MAXQ2010 Supplement - Manual (Page 52)

MAXQ Family User’s Guide:
MAXQ2010 Supplement
6-14
6.1.30 External Interrupt Edge Select 2 Register (EIES2, M1[0Ch])
Each bit in this register controls the edge select mode for an external interrupt as follows:
0 = The external interrupt triggers on a rising (positive) edge.
1 = The external interrupt triggers on a negative (falling) edge.
Bit 7: Edge Select for External Interrupt 22 (IT22)
Bit 6: Edge Select for External Interrupt 21 (IT21)
Bit 5: Edge Select for External Interrupt 20 (IT20)
Bit 4: Edge Select for External Interrupt 19 (IT19)
Bit 3: Edge Select for External Interrupt 18 (IT18)
Bit 2: Edge Select for External Interrupt 17 (IT17)
Bit 1: Edge Select for External Interrupt 16 (IT16)
Bit 0: Edge Select for External Interrupt 15 (IT15)
6.2 GPIO and External Interrupt Code Examples
6.2.1 GPIO Example 1: Driving Outputs on Port 0
move PO0, #000h ; Set all outputs low
move PD0, #0FFh ; Set all P0 pins to output mode
6.2.2 GPIO Example 2: Receiving Inputs on Port 1
move PO1, #0FFh ; Set weak pullups ON on all pins
move PD1, #000h ; Set all P1 pins to input mode
nop ; Wait for external source to drive P1 pins
move Acc, PI1 ; Get input values from P1 (will return FF if
; no other source drives the pins low)
Bit # 7 6 5 4 3 2 1 0
Name IT22 IT21 IT20 IT19 IT18 IT17 IT16 IT15
Reset 0 0 0 0 0 0 0 0
Access rw rw rw rw rw rw rw rw