Maxim-integrated MAXQ Family Users Guide: MAXQ2010 Supplement Manual de usuario descargar pdf (Pagina 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

1 2 ... 47 48 49 50 51 52 53 54 55 56 57 ... 146 147

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Maxim-integrated MAXQ Family Users Guide: MAXQ2010 Supplement Manual de usuario Pagina 52