General Description
MC68HC908GR8 MC68HC908GR4 Data Sheet, Rev. 7
20
Freescale Semiconductor
7680 bytes of on-chip FLASH memory on the MC68HC908GR8 and 4096 bytes of on-chip FLASH
memory on the MC68HC908GR4 with in-circuit programming capabilities of FLASH program
memory
384 bytes of on-chip random-access memory (RAM)
Serial peripheral interface module (SPI)
Serial communications interface module (SCI)
One 16-bit, 2-channel timer (TIM1) and one 16-bit, 1-channel timer (TIM2) interface modules with
selectable input capture, output compare, and PWM capability on each channel
6-channel, 8-bit successive approximation analog-to-digital converter (ADC)
BREAK module (BRK) to allow single breakpoint setting during in-circuit debugging
Internal pullups on IRQ and RST to reduce customer system cost
Clock generator module with on-chip 32-kHz crystal compatible PLL (phase-lock loop)
Up to 21 general-purpose input/output (I/O) pins, including:
–
19 shared-function I/O pins
–
Up to two 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/10-mA source capability on all port pins
Higher current 15-mA sink/source capability on PTC0–PTC1
Timebase module 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 32-kHz crystal
Oscillator stop mode enable bit (OSCSTOPENB) in the CONFIG register to allow user selection of
having the oscillator enabled or disabled during stop mode
4-bit keyboard wakeup port
42-pin shrink dual in-line package (SDIP), 32-pin quad flat pack (QFP), 28-pin plastic dual-in-line
package (DIP), or 28-pin small outline integrated circuit (SOIC)
Specific features of the MC68HC908GR8 in 28-pin DIP and 28-pin SOIC are:
–
Port B is only 4 bits: PTB0–PTB3; 4-channel ADC module
–No Port C bits
1.2.2 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