●General Description
●Introduction
●The MC68HC908GT16, MC68HC908GT8, and MC68HC08GT16 are members 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 MC68HC908GT16/MC68HC908GT8
●• Features of the CPU08
●Standard Features of the MC68HC908GT16/MC68HC908GT8
●• High-performance M68HC08 architecture optimized for C-compilers
●• Fully upward-compatible object code with M6805, M146805, and M68HC05 Families
●• 8-MHz internal bus frequency
●• Internal oscillator requiring no external components:
● – Software selectable bus frequencies
● – ±25 percent accuracy with trim capability to ±4 percent
● – Clock monitor
● – Option to allow use of external clock source or external crystal/ceramic resonator
●• 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 3.0-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 (8 Kbytes on MC68HC908GT8)
●• 512 bytes of on-chip random-access memory (RAM)
●• 720 bytes of Flash programming routines ROM
●• Serial peripheral interface module (SPI)
●• Serial communications interface module (SCI)
●• Two 16-bit, 2-channel timer interface modules (TIM1 and TIM2) with selectable input capture, output compare, and pulse-width modulation (PWM) capability on each channel
●• 8-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
●• Up to 36 general-purpose input/output (I/O) pins, including:
● – 28 shared-function I/O pins
● – Six or eight 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 20-mA sink/source capability on PTC0–PTC4
●• 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 or internal oscillator
●• User selection of having the oscillator enabled or disabled during stop mode
●• 8-bit keyboard wakeup port
●• Available packages:
● – 42-pin shrink dual in-line package (SDIP)
● – 44-pin quad flat pack (QFP)
●• Specific features of the MC68HC908GT16 in 42-pin SDIP are:
● – Port C is only 5 bits: PTC0–PTC4
● – Port D is 8 bits: PTD0–PTD7; dual 2-channel TIM modules
●• Specific features of the MC68HC908GT16 in 44-pin QFP are:
● – Port C is 7 bits: PTC0–PTC6
● – Port D is 8 bits: PTD0–PTD7; dual 2-channel TIM modules
