COM1 SERIAL PORT

TXD0

RXD0

GND

1

26

37

48

59

The COM-1port has a Female DB9 connector that interfaces to 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.

Handshake pins can be easily isolated and connected to I/O ports if necessary.

J2

1

2

3

4

T2IN

The J2 connector (near COM1) contains spare RS232 translator inputs

R2OUT

and outputs. It can be used for implementing hardware handshaking on

R2IN

COM1 if necessary.

T2OUT

 

BUS_PORT

The BUS_PORT supports off-board memory devices as follows:

GND D10 D9 D8 A0 A1 A10

/OE A11 A9 A8 A12

/WE CS1 CS3 CS5 +5V /RW

E GND

12

34

56

78

910

1112

1314

1516

1718

1920

2122

2324

2526

2728

2930

3132

3334

3536

3738

3940

D11

D12

D13

D14

D15

A2

A3

A4

A5

A6

A7

A13

CS0

CS2

CS4

IRQ /P-SEL CS6 CS7

/ RESET

D8 - D15 High Byte Data Bus in Wide Expanded Mode and 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.

CS0 – CS7 Peripheral chip selects, 16 bytes each located at $200 - $27F hex, 8 bit access (narrow bus).

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

IRQ HC12 IRQ (PE1) Interrupt Input.

/RW HC12 Read/Write (PE2) control signal.

EHC12 ECLK (PE4) bus clock signal. Stretch should be enabled in software.

/P-SELSelects Peripheral area, register following space, 8 bits

wide.

/RESET HC12 active low RESET signal.

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Motorola 68HC12B32, 68HC12BC32, CME-12B/BC manual COM1 Serial Port, Busport

68HC12B32, CME-12B/BC, 68HC12BC32 specifications

The Motorola 68HC12BC32, CME-12B/BC, and 68HC12B32 are microcontroller units (MCUs) that are part of the renowned HC12 series, which gained popularity in embedded system designs due to their versatility, robust performance, and comprehensive feature set. These MCUs are widely used in automotive applications, industrial control systems, and various consumer electronics due to their advanced capabilities.

One of the main features of the 68HC12BC32 is its 16-bit architecture, which allows for efficient processing and greater precision in calculations compared to 8-bit counterparts. This feature is crucial for applications requiring high-performance processing, such as real-time control systems. The processor operates at clock speeds of up to 25 MHz, providing the computational power necessary for complex operations.

The 68HC12MCUs include various on-chip memory options, such as ROM, RAM, and EEPROM. For instance, the 68HC12BC32 comes with up to 32 KB of ROM and 1 KB of RAM, along with 512 bytes of EEPROM, making it suitable for applications that require data retention even when the power is turned off. The presence of on-chip memory significantly reduces the need for external components, simplifying system design and enhancing reliability.

Moreover, these microcontrollers feature a rich set of input/output (I/O) capabilities, including multiple general-purpose I/O lines, timer/counter modules, and analog-to-digital converters (ADCs). The integration of these components allows for flexible interfacing with a multitude of sensors and actuators, enabling designers to create sophisticated applications without needing extensive external circuitry.

The embedded communication interfaces, such as SPI (Serial Peripheral Interface), I2C (Inter-Integrated Circuit), and CAN (Controller Area Network), are vital for enabling communication between devices in multiprocessor systems. This capability is particularly beneficial in automotive applications, where seamless data exchange is critical for tasks such as engine control and diagnostics.

Power management features in the 68HC12 series enhance its suitability for battery-powered applications. The ability to enter low-power modes helps extend battery life, making these microcontrollers ideal for portable devices.

In summary, the Motorola 68HC12BC32, CME-12B/BC, and 68HC12B32 microcontrollers are robust and flexible MCUs that offer a combination of advanced processing capabilities, extensive memory options, versatile I/O functionality, and efficient communication interfaces. These characteristics make them well-suited for various applications, from automotive and industrial systems to consumer electronics, ensuring they remain relevant in the evolving landscape of embedded technology.