Motorola MC9S12DP256 User Manual

C M L 1 2 S D P 2 5 6

0 7 / 1 7 / 0 2

GND

D11/PA3

PA2/D10

D12/PA4

PA1/D9

D13/PA5

PA0/D8

D14/PA6

A0

9 10 D15/PA7

A1 11 12 A2

A10 13 14 A3

OE* 15 16 A4

A11 17 18 A5

A9 19 20 A6
A8 21 22 A7

A12 23 24 A13

WE*

25 26 A14

PE3/LSTRB* 27 28 A15

PE5/MODA 29 30 PE7/NOACC **
PE6/MODB 31 32 PE1/IRQ*

+5V 33 34 PE0/ XIRQ*

PE2/RW

35 36 RESERVED

PE4/ECLK 37 38 RESERVED

GND 39 40 RESET*

The BUS_PORT supports off-board memory devices
while the HCS12 is in expanded mode.

PA0/D8 - PA7/D15 High Byte Data Bus in Wide
Expanded Mode.  Port A in Single Chip Mode.

A0 – A15  Latched Memory Addresses 0 to 15.

OE*  Memory Output Enable signal, Active Low.  Valid
with ECLK and R/W high.

WE*  Memory Write Enable signal, Active Low.  Valid
with ECLK high and R/W low.

RESET*  HCS12 active low RESET signal.

The KEYPAD / PORT H connector provides interface for the HCS12 port H or applying a
keypad such as the Axiom Mfg. HC-KP. When applied as a KEYPAD connector, the interface
is for a passive 4 x 4 matrix (16 key) keypad device.

PH0

PH1

PH2

PH3

PH4

PH5

PH6

PH7

This interface is implemented as a software key scan.  Pins PH0-3 are
used as column drivers which are active high outputs. Pins PH4-7 are
used for row input and will read high when their row is high.

See the file Key12Dx.ASM  for an example program using this
connector.

1 1

6

TXD0 2 6 7

RXD0 3 7 8

4 4 8 9

GND 5 9 X

The COM-1 port has a Female DB9 connector that interfaces to
the HCS12 internal SCI0 serial port via the U11 RS232
transceiver.  It uses a simple 2 wire asynchronous serial
interface and is translated to RS232 signaling levels.
1,4,6 connected and 7,8 connected