8-bit QB MCUs

Block Diagram

NXP S08QB Microcontroller Block Diagram

Freescale S08QB Microcontroller Block Diagram


Power-Saving Features

  • Two ultra-low-power stop modes, one of which allows limited use of peripherals
  • New low-power run and wait modes
  • 6 µs typical wake up time from stop mode
  • Internal clock Source (ICS)—module containing a frequency locked-loop (FLL) controlled by internal or external reference
  • Oscillator (OSC)—loop-control Pierce oscillator
    • crystal or ceramic resonator range of 31.25 kHz to 38.4 kHz or 1 MHz to 16 MHz
  • Clock gating disables clocks to unused peripherals

8-bit HCS08 Central Processing Unit (CPU)

  • Up to 20 MHZ HCS08 CPU from 1.8V to 3.6V and across temperature range of -40°C to +85°C
  • HCS08 instruction set with added BGND instruction

On-Chip Memory

  • Up to 8 KB flash read/program/erase over full operating voltage and temperature
  • Up to 512 bytes of random access memory(RAM) with low ram retention voltage and security feature


  • ADC—8-channel
    • 12-bit resolution for 28-pin and 24-pin packages
    • 10-bit resolution for 16-pin package
    • 2.5 µs conversion time for both 10-bit and 12-bit resolution
    • Automatic compare function
    • Internal temperature sensor
    • Internal bandgap reference channel
    • Operation in low-power stop mode
  • Timer/pulse-width modulator (TPM)
    • One channel with 16-bit counter
    • Selectable input capture
    • Output compare
    • Buffered edge- or centeraligned PWM
    • Located at PTA0 by default but it can also be selected by software to relocate at PTB5 port
  • Serial communications interface (SCI)
    • Offering asynchronous communications
    • 13-bit break option
    • Flexible baud rate generator
    • Optional H/W parity checking and generation
  • Analog comparator (ACMP)
    • Option to compare to an internal reference voltage
    • Output can be optionally routed to TPM as input capture trigger
  • 8-bit module timer module with 8-bit prescaler (MTIM)


  • Up to 22 general purpose input/output (GPIO), one input-only and one output-only pin
  • 8 keyboard interrupts (KBI) pins with selectable polarity

System Protection

  • Watchdog computer operating properly (COP) reset with option to run from dedicated 1 kHz internal clock source or bus clock
  • Low-voltage detection with reset or interrupt, selectable trip points
  • Illegal op code and illegal address detection with reset
  • Flash block protection

Development Support

  • Breakpoint capability

Part numbers include: MC9S08QB4CGK, MC9S08QB4CTG, MC9S08QB4CWL, MC9S08QB8CGK, MC9S08QB8CTG, MC9S08QB8CWL.


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Design Resources


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Note: For better experience, software downloads are recommended on desktop.