IRST

RST

CGMXCLK

IAB

RSTPULLEDLOWBYMCU

32 CYCLES

32 CYCLES

VECTOR HIGH

Figure 7-5. Internal Reset Timing

The COP reset is asynchronous to the bus clock.

ILLEGAL ADDRESS RST ILLEGAL OPCODE RST COPRST

POR

USB

INTERNAL RESET

Figure 7-6. Sources of Internal Reset

The active reset feature allows the part to issue a reset to peripherals and other chips within a system built around the MCU.

7.4.2.1 Power-On Reset

When power is first applied to the MCU, the power-on reset module (POR) generates a pulse to indicate that power-on has occurred. The external reset pin (RST) is held low while the SIM counter counts out 4096 CGMXCLK cycles. Sixty-four CGMXCLK cycles later, the CPU and memories are released from reset to allow the reset vector sequence to occur. At power-on, the following events occur:

• A POR pulse is generated.

• The internal reset signal is asserted.

• The SIM enables the oscillator to drive CGMXCLK.

• Internal clocks to the CPU and modules are held inactive for 4096 CGMXCLK cycles to allow stabilization of the oscillator.

• The RST pin is driven low during the oscillator stabilization time.

• The POR bit of the reset status register (RSR) is set and all other

 

bits in the register are cleared.

Advance Information

MC68HC(7)08KH12 — Rev. 1.1

 

 

 

 

68

Freescale Semiconductor

Page 67 Page 69
Page 68
Image 68
Freescale Semiconductor MC68HC08KH12 manual COP reset is asynchronous to the bus clock, Power-On Reset
Page 67 Page 69

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.
Top Page Image Contents