Introduction

The MC68HC908GR16 is a member of the low-cost, high-performance M68HC08 Family of 8-bit microcontroller units (MCUs). All MCUs in the family use the enhanced M68HC08 central processor unit (CPU08) and are available with a variety of modules, memory sizes and types, and package types.

Features

For convenience, features have been organized to reflect:

• Standard features of the MC68HC908GR16

• Features of the CPU08

Standard Features of the MC68HC908GR16

Features of the MC68HC908GR16 include:

• High-performance M68HC08 architecture optimized for C-compilers

• Fully upward-compatible object code with M6805, M146805, and M68HC05 Families

• 8-MHz internal bus frequency

• Clock generation module supporting 32-kHz to 100-kHz crystals

• FLASH program memory security(1)

• On-chip programming firmware for use with host personal computer which does not require high voltage for entry

• In-system programming (ISP)

• System protection features:

– Optional computer operating properly (COP) reset

– Low-voltage detection with optional reset and selectable trip points for 3.3-V and 5.0-V operation

– Illegal opcode detection with reset

– Illegal address detection with reset

• Low-power design; fully static with stop and wait modes

• Standard low-power modes of operation:

– Wait mode

– Stop mode

• Master reset pin and power-on reset (POR)

• 16 Kbytes of on-chip 100k cycle write/erase capable FLASH memory

• 1 Kbyte of on-chip random-access memory (RAM)

• 406 bytes of FLASH programming routines read-only memory (ROM)

• Serial peripheral interface (SPI) module

• Enhanced serial communications interface (ESCI) module

• Two 16-bit timer interface modules (2-channel TIM1 and 2-channel TIM2) with selectable input capture, output compare, and pulse-width modulation (PWM) capability on each channel

• 8-channel, 10-bit successive approximation analog-to-digital converter (ADC)

• BREAK (BRK) module to allow single breakpoint setting during in-circuit debugging

• Internal pullups on IRQ and RST to reduce customer system cost

• Up to 37 general-purpose input/output (I/O) pins, including:

– 28 shared-function I/O pins

– Up to nine dedicated I/O pins, depending on package choice

• Selectable pullups on inputs only on ports A, C, and D. Selection is on an individual port bit basis. During output mode, pullups are disengaged.

• High current 10-mA sink/source capability on all port pins

• Higher current 20-mA sink/source capability on PTC0–PTC4

• Timebase module (TBM) with clock prescaler circuitry for eight user selectable periodic real-time interrupts with optional active clock source during stop mode for periodic wakeup from stop using an external crystal

• User selection of having the oscillator enabled or disabled during stop mode

• 8-bit keyboard wakeup port

• 5 mA maximum current injection on all port pins to maintain input protection

• Available packages:

– 32-pin LQFP

– 48-pin low-profile quad flag pack (LQFP)

• Specific features of the MC68HC908GR16 in 32-pin LQFP are:

– Port A is only 4 bits: PTA0–PTA3; 4-pin keyboard interrupt (KBI) module

– Port B is only 6 bits: PTB0–PTB5; 6-channel ADC module

– Port C is only 2 bits: PTC0–PTC1

– Port D is only 7 bits: PTD0–PTD6; shared with SPI, TIM1, and TIM2 modules

– Port E is only 2 bits: PTE0–PTE1; shared with ESCI module

• Specific features of the MC68HC908GR16 in 48-pin LQFP are:

– Port A is 8 bits: PTA0–PTA7; 8-pin KBI module

– Port B is 8 bits: PTB0–PTB7; 8-channel ADC module

– Port C is only 7 bits: PTC0–PTC6

– Port D is 8 bits: PTD0–PTD7; shared with SPI, TIM1, and TIM2 modules

– Port E is only 6 bits: PTE0–PTE5; shared with ESCI module

Features of the CPU08

Features of the CPU08 include:

• Enhanced HC05 programming model

• Extensive loop control functions

• 16 addressing modes (eight more than the HC05)

• 16-bit index register and stack pointer

• Memory-to-memory data transfers

• Fast 8 × 8 multiply instruction

• Fast 16/8 divide instruction

• Binary-coded decimal (BCD) instructions

• Optimization for controller applications

• Efficient C language support