231

4.Write to the ACKE bit in the keyboard status and control register to clear any false interrupts.

5.Clear the IMASKE bit.

An interrupt signal on an edge-triggered pin can be acknowledged immediately after enabling the pin. An interrupt signal on an edge- and level-triggered interrupt pin must be acknowledged after a delay that depends on the external load.

15.5.3 Port-E Keyboard Interrupt Registers

15.5.3.1Port-E Keyboard Status and Control Register

•Flags keyboard interrupt requests.

•Acknowledges keyboard interrupt requests.

•Masks keyboard interrupt requests.

•Controls keyboard interrupt triggering sensitivity.

Address:

Read:

Write:

Reset:

$000E
Bit 7	6	5	4	3	2	1	Bit 0

0	0	0	0	KEYEF	0	IMASKE	MODEE

					ACKE
					ACKE

0	0	0	0	0	0	0	0
	= Unimplemented
	= Unimplemented

Figure 15-5. Port-E Keyboard Status and Control Register (KBESCR)

Bits [7:4] — Not used

These read-only bits always read as logic 0s.

KEYEF — Port-E Keyboard Flag Bit

This read-only bit is set when a keyboard interrupt is pending on port-E. Reset clears the KEYEF bit.

1 = Keyboard interrupt pending

0 = No keyboard interrupt pending

MC68HC(7)08KH12 — Rev. 1.1	Advance Information

Freescale Semiconductor	231

MC68HC08KH12 specifications

The Freescale Semiconductor MC68HC08KH12 is a versatile microcontroller that has gained popularity in various embedded systems applications. Part of the HC08 family, this microcontroller combines a robust architecture with comprehensive on-chip features, making it suitable for a wide range of applications ranging from industrial control to consumer electronics.

One of the main features of the MC68HC08KH12 is its 8-bit architecture, which provides an optimal balance between performance and power efficiency. It operates at clock speeds of up to 2 MHz, allowing for efficient execution of instructions while maintaining low power consumption. The microcontroller is designed to operate over a voltage range of 2.7 to 5.5 volts, making it adaptable to various system requirements.

The MC68HC08KH12 is equipped with 1 Kbyte of RAM and 12 Kbytes of ROM, which allows for substantial program and data storage. The on-chip memory helps reduce the need for external components, simplifying the design of embedded systems and enhancing reliability. With a wide range of I/O options, including 26 general-purpose I/O pins, the microcontroller provides flexibility in interfacing with sensors, actuators, and other devices.

In terms of technologies, the MC68HC08KH12 features an advanced instruction set that enhances programming efficiency. It supports basic arithmetic operations, bit manipulation, and control transfer instructions, making it suitable for a variety of computational tasks. The integrated timers, analog-to-digital converters, and serial communication interfaces, including UART, provide the necessary tools for real-time control and data exchange with peripheral devices.

Another characteristic of the MC68HC08KH12 is its low power mode capabilities, which allow it to enter a sleep state during periods of inactivity. This feature is essential in battery-powered applications, where minimizing power consumption is crucial for extending operational life.

Overall, the Freescale Semiconductor MC68HC08KH12 stands out as a reliable microcontroller that combines performance, flexibility, and power efficiency. Its extensive features and technologies enable engineers to design robust embedded systems that meet the demands of modern applications. As a result, the MC68HC08KH12 remains a valuable choice for developers seeking a highly functional yet cost-effective microcontroller solution.

Freescale Semiconductor MC68HC08KH12 manual Port-E Keyboard Status and Control Register, 231

Models: MC68HC08KH12

15.5.3.1Port-E Keyboard Status and Control Register

Figure 15-5. Port-E Keyboard Status and Control Register (KBESCR)

MC68HC08KH12 specifications