3822 datasheet(95/328 Pages) RENESAS

95 / 328 page

2.2 Interrupts

APPLICATION

2–29

3822 GROUP USER’S MANUAL

2.2.5 Key input interrupt

The Key input interrupt request occurs when an “L” level voltage is applied to the pin set for the input mode

of the port P2.

For interrupt sources except the INT interrupts and the Key input interrupt, refer to “CHAPTER 1”.

(1) Connection example when the Key input interrupt is used

When using the Key input interrupt, after set ports P20 to P23 for the input mode, configure an “L” level

valid key-matrix.

Figure 2.2.15 shows a connection example when the key input interrupt is used, and a port P2 block

diagram. In the connection example in Figure 2.2.15, an Key input interrupt request is caused by

pressing the key corresponding to one of ports P20 to P23.

Fig. 2.2.15 Connection example when key input interrupt is used, and port P2 block diagram

V1: P-channel transistor for pull-up

V2: CMOS output buffer

Port P20

latch

Port P2 direction register, b0 = “0”

Port P21

latch

Port P2 direction register, b1 = “0”

Port P22

latch

Port P2 direction register, b2 = “0”

Port P23

latch

Port P2 direction register, b3 = “0”

Port P24

latch

Port P2 direction register, b4 = “1”

Port P25

latch

Port P2 direction register, b5 = “1”

Port P26

latch

Port P2 direction register, b6 = “1”

Port P27

latch

Port P2 direction register, b7 = “1”

P27

output

Port PXx “L” level output

PULL register A, b2 = “1”

Port P2 input

reading circuit

Key input interrupt request

P26

output

P25

output

P24

output

P23

input

P22

input

P21

input

P20

input

3822 Datasheet(PDF) 95 Page - Renesas Technology Corp

3822 Datasheet(HTML) 95 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL