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