HC805K3GRSSLASHD datasheet(62/119 Pages) NXP

62 / 119 page

General Release Speciﬁcation

Port A

MC68HC805K3 — Rev. 1.0

Parallel Input/Output

The PDRA is a write-only register and any reads of location $0010 return

undefined results. Since reset clears both the DDRA and the PDRA, all

pins initialize as inputs with the pulldown devices active (if enabled by

mask option register bit).

7.3.4 Port A LED Drive Capability

The outputs of port A pins 4 through 7 are capable of sinking high current

for LED drive capability.

7.3.5 Port A I/O Pin Interrupts

The inputs for the lower four bits of port A can be connected through an

OR gate to the IRQ latched input to the CPU by a mask option register

bit. When connected as an alternate source of an IRQ interrupt, the port

A input pins behave the same as the IRQ pin itself, except that their

active state is a logical one or a rising edge. The normal IRQ pin has an

active state that is a logical zero or a falling edge depending on the mask

option register bit.

If the mask option register bit for edge- and level-sensitive interrupts and

the mask option register bit for port A interrupts are both used, the

presence of a logic one on any one of the lower four port A pins causes

an IRQ interrupt request. If the mask option register bit for edge-

sensitive-only interrupts and the mask option register bit for port A

interrupts are both used, the occurrence of a rising edge on any one of

the PA0–PA3 pins causes an IRQ interrupt request, as long as the other

PA0–PA3 pins are at a low level. As long as any one of the PA0 through

PA3 IRQ inputs remains at a logic one level, or the IRQ remains at a

$0010

Bit 7

65432

Bit 0

Read:

Write:

PDIA7

PDIA6

PDIA5

PDIA4

PDIA3

PDIA2

PDIA1

PDIA0

Reset:

00000

= Unimplemented

Figure 7-2. Port A Pulldown Inhibit Register (PDRA)

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

HC805K3GRS/D Datasheet(PDF) 62 Page - NXP Semiconductors

HC805K3GRS/D Datasheet(HTML) 62 Page - NXP Semiconductors

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