Motorola 68HC12B32 User Manual
13
COM1 SERIAL PORT
1
TXD0 2 6
RXD0 3 7
4
8
GND 5 9
The COM-1 port has a Female DB9 connector that interfaces to
the HC12 internal SCI0 serial port. It uses a simple 2 wire
asynchronous serial interface.
the HC12 internal SCI0 serial port. It uses a simple 2 wire
asynchronous serial interface.
Pins 1, 4, and 6 are connected for default handshake standards.
Pins 7 and 8 are connected for default handshake standards.
Pins 7 and 8 are connected for default handshake standards.
Handshake pins can be easily isolated and connected to I/O ports if necessary.
J2
1
T2IN
2
R2OUT
3
R2IN
4
T2OUT
The J2 connector (near COM1) contains spare RS232 translator inputs
and outputs. It can be used for implementing hardware handshaking on
COM1 if necessary.
and outputs. It can be used for implementing hardware handshaking on
COM1 if necessary.
BUS_PORT
The BUS_PORT supports off-board memory devices as follows:
GND
1 2
D11
D10
3 4
D12
D9
5 6
D13
D8
7 8
D14
A0
9 10 D15
A1 11 12 A2
A10 13 14 A3
/ OE 15 16 A4
A11 17 18 A5
A9 19 20 A6
A8 21 22 A7
A8 21 22 A7
A12 23 24 A13
/ WE
25 26 CS0
CS1 27 28 CS2
CS3 29 30 CS4
CS5 31 32 IRQ
CS3 29 30 CS4
CS5 31 32 IRQ
+5V 33 34 /P-SEL
/RW
35 36 CS6
E 37 38 CS7
GND 39 40 / RESET
D8 - D15 High Byte Data Bus in Wide Expanded Mode and
Peripheral 8 bit data bus. Port A in Single Chip Mode.
Peripheral 8 bit data bus. Port A in Single Chip Mode.
A0 – A15 Memory Addresses 0 to 15.
/OE Memory Output Enable signal, Active Low. Valid with ECLK
and R/W high.
and R/W high.
CS0 – CS7 Peripheral chip selects, 16 bytes each located at
$200 - $27F hex, 8 bit access (narrow bus).
$200 - $27F hex, 8 bit access (narrow bus).
/WE Memory Write Enable signal, Active Low. Valid with ECLK
high and R/W low.
high and R/W low.
IRQ HC12 IRQ (PE1) Interrupt Input.
/RW HC12 Read/Write (PE2) control signal.
E HC12 ECLK (PE4) bus clock signal. Stretch should be enabled
in software.
in software.
/P-SEL Selects Peripheral area, register following space, 8 bits
wide.
wide.
/RESET HC12 active low RESET signal.