Datasheet
Table Of Contents
- Section 1. General Description
- 1.1 Contents
- 1.2 Introduction
- 1.3 Features
- 1.3.1 Standard Features of the MC68HC908GP20
- 1.3.2 Features of the CPU08
- 1.4 MCU Block Diagram
- 1.5 Pin Assignments
- 1.6 Pin Functions
- 1.6.1 Power Supply Pins (VDD and VSS)
- 1.6.2 Oscillator Pins (OSC1 and OSC2)
- 1.6.3 External Reset Pin (RST)
- 1.6.4 External Interrupt Pin (IRQ)
- 1.6.5 CGM Power Supply Pins (VDDA and VSSA)
- 1.6.6 External Filter Capacitor Pin (CGMXFC)
- 1.6.7 Analog Power Supply Pins (VDDAD and VSSAD)
- 1.6.8 ADC Voltage Reference High Pin (VREFH)
- 1.6.9 ADC Voltage Reference Low Pin (VREFL)
- 1.6.10 Port A Input/Output (I/O) Pins (PTA7/KBD7-PTA0/KBD0)
- 1.6.11 Port B I/O Pins (PTB7/AD7-PTB0/AD0)
- 1.6.12 Port C I/O Pins (PTC6-PTC0)
- 1.6.13 Port D I/O Pins (PTD7/T2CH1-PTD0/SS)
- 1.6.14 Port E I/O Pins (PTE1/RxD-PTE0/TxD)
- Section 2. Memory Map
- Section 3. Low-Power Modes
- 3.1 Contents
- 3.2 Introduction
- 3.2.1 Wait Mode
- 3.2.2 Stop Mode
- 3.3 Analog-to-Digital Converter (ADC)
- 3.3.1 Wait Mode
- 3.3.2 Stop Mode
- 3.4 Break Module (BRK)
- 3.4.1 Wait Mode
- 3.4.2 Stop Mode
- 3.5 Central Processor Unit (CPU)
- 3.5.1 Wait Mode
- 3.5.2 Stop Mode
- 3.6 Clock Generator Module (CGM)
- 3.6.1 Wait Mode
- 3.6.2 Stop Mode
- 3.7 Computer Operating Properly Module (COP)
- 3.7.1 Wait Mode
- 3.7.2 Stop Mode
- 3.8 External Interrupt Module (IRQ)
- 3.8.1 Wait Mode
- 3.8.2 Stop Mode
- 3.9 Keyboard Interrupt Module (KBI)
- 3.9.1 Wait Mode
- 3.9.2 Stop Mode
- 3.10 Low-Voltage Inhibit Module (LVI)
- 3.10.1 Wait Mode
- 3.10.2 Stop Mode
- 3.11 Serial Communications Interface Module (SCI)
- 3.11.1 Wait Mode
- 3.11.2 Stop Mode
- 3.12 Serial Peripheral Interface Module (SPI)
- 3.12.1 Wait Mode
- 3.12.2 Stop Mode
- 3.13 Timer Interface Module (TIM1 and TIM2)
- 3.13.1 Wait Mode
- 3.13.2 Stop Mode
- 3.14 Timebase Module (TBM)
- 3.14.1 Wait Mode
- 3.14.2 Stop Mode
- 3.15 Exiting Wait Mode
- 3.16 Exiting Stop Mode
- Section 4. Resets and Interrupts
- Section 5. Analog-to-Digital Converter (ADC)
- 5.1 Contents
- 5.2 Introduction
- 5.3 Features
- 5.4 Functional Description
- 5.4.1 ADC Port I/O Pins
- 5.4.2 Voltage Conversion
- 5.4.3 Conversion Time
- 5.4.4 Conversion
- 5.4.5 Accuracy and Precision
- 5.5 Interrupts
- 5.6 Low-Power Modes
- 5.6.1 Wait Mode
- 5.6.2 Stop Mode
- 5.7 I/O Signals
- 5.7.1 ADC Analog Power Pin (VDDAD)/ADC Voltage Reference High Pin (VREFH)
- 5.7.2 ADC Analog Ground Pin (VSSAD)/ADC Voltage Reference Low Pin (VREFL)
- 5.7.3 ADC Voltage In (ADVIN)
- 5.8 I/O Registers
- 5.8.1 ADC Status and Control Register
- 5.8.2 ADC Data Register
- 5.8.3 ADC Clock Register
- Section 6. Break Module (BRK)
- 6.1 Contents
- 6.2 Introduction
- 6.3 Features
- 6.4 Functional Description
- 6.4.1 Flag Protection During Break Interrupts
- 6.4.2 CPU During Break Interrupts
- 6.4.3 TIMI and TIM2 During Break Interrupts
- 6.4.4 COP During Break Interrupts
- 6.5 Low-Power Modes
- 6.5.1 Wait Mode
- 6.5.2 Stop Mode
- 6.6 Break Module Registers
- 6.6.1 Break Status and Control Register
- 6.6.2 Break Address Registers
- 6.6.3 Break Status Register
- 6.6.4 Break Flag Control Register
- Section 7. Clock Generator Module (CGMC)
- 7.1 Contents
- 7.2 Introduction
- 7.3 Features
- 7.4 Functional Description
- 7.4.1 Crystal Oscillator Circuit
- 7.4.2 Phase-Locked Loop Circuit (PLL)
- 7.4.3 PLL Circuits
- 7.4.4 Acquisition and Tracking Modes
- 7.4.5 Manual and Automatic PLL Bandwidth Modes
- 7.4.6 Programming the PLL
- 7.4.7 Special Programming Exceptions
- 7.4.8 Base Clock Selector Circuit
- 7.4.9 CGMC External Connections
- 7.5 I/O Signals
- 7.5.1 Crystal Amplifier Input Pin (OSC1)
- 7.5.2 Crystal Amplifier Output Pin (OSC2)
- 7.5.3 External Filter Capacitor Pin (CGMXFC)
- 7.5.4 PLL Analog Power Pin (Vdda)
- 7.5.5 PLL Analog Ground Pin (Vssa)
- 7.5.6 Oscillator Enable Signal (SIMOSCEN)
- 7.5.7 Oscillator Stop Mode Enable Bit (OSCSTOPENB)
- 7.5.8 Crystal Output Frequency Signal (CGMXCLK)
- 7.5.9 CGMC Base Clock Output (CGMOUT)
- 7.5.10 CGMC CPU Interrupt (CGMINT)
- 7.6 CGMC Registers
- 7.6.1 PLL Control Register
- 7.6.2 PLL Bandwidth Control Register
- 7.6.3 PLL Multiplier Select Register High
- 7.6.4 PLL Multiplier Select Register Low
- 7.6.5 PLL VCO Range Select Register
- 7.6.6 PLL Reference Divider Select Register
- 7.7 Interrupts
- 7.8 Special Modes
- 7.8.1 Wait Mode
- 7.8.2 Stop Mode
- 7.8.3 CGMC During Break Interrupts
- 7.9 Acquisition/Lock Time Specifications
- 7.9.1 Acquisition/Lock Time Definitions
- 7.9.2 Parametric Influences on Reaction Time
- 7.9.3 Choosing a Filter
- Section 8. Configuration Register (CONFIG)
- Section 9. Computer Operating Properly (COP)
- 9.1 Contents
- 9.2 Introduction
- 9.3 Functional Description
- 9.4 I/O Signals
- 9.4.1 CGMXCLK
- 9.4.2 STOP Instruction
- 9.4.3 COPCTL Write
- 9.4.4 Power-On Reset
- 9.4.5 Internal Reset
- 9.4.6 Reset Vector Fetch
- 9.4.7 COPD (COP Disable)
- 9.4.8 COPRS (COP Rate Select)
- 9.5 COP Control Register
- 9.6 Interrupts
- 9.7 Monitor Mode
- 9.8 Low-Power Modes
- 9.8.1 Wait Mode
- 9.8.2 Stop Mode
- 9.9 COP Module During Break Mode
- Section 10. Central Processor Unit (CPU)
- 10.1 Contents
- 10.2 Introduction
- 10.3 Features
- 10.4 CPU Registers
- 10.4.1 Accumulator
- 10.4.2 Index Register
- 10.4.3 Stack Pointer
- 10.4.4 Program Counter
- 10.4.5 Condition Code Register
- 10.5 Arithmetic/Logic Unit (ALU)
- 10.6 Low-Power Modes
- 10.6.1 Wait Mode
- 10.6.2 Stop Mode
- 10.7 CPU During Break Interrupts
- 10.8 Instruction Set Summary
- 10.9 Opcode Map
- Section 11. FLASH Memory
- 11.1 Contents
- 11.2 Introduction
- 11.3 Functional Description
- 11.4 FLASH Control Register
- 11.5 Charge Pump
- 11.5.1 FLASH Charge Pump Frequency Control
- 11.5.2 Voltage Regulator
- 11.6 FLASH Erase Operation
- 11.7 FLASH Program/Margin Read Operation
- 11.8 FLASH Block Protection
- 11.9 FLASH Block Protect Register
- 11.10 Wait Mode
- 11.11 Stop Mode
- Section 12. External Interrupt (IRQ)
- Section 13. Keyboard Interrupt Module (KBI)
- Section 14. Low-Voltage Inhibit (LVI)
- Section 15. Monitor ROM (MON)
- Section 16. Input/Output (I/O) Ports
- 16.1 Contents
- 16.2 Introduction
- 16.3 Port A
- 16.3.1 Port A Data Register
- 16.3.2 Data Direction Register A
- 16.3.3 Port A Input Pullup Enable Register
- 16.4 Port B
- 16.4.1 Port B Data Register
- 16.4.2 Data Direction Register B
- 16.5 Port C
- 16.5.1 Port C Data Register
- 16.5.2 Data Direction Register C
- 16.5.3 Port C Input Pullup Enable Register
- 16.6 Port D
- 16.6.1 Port D Data Register
- 16.6.2 Data Direction Register D
- 16.6.3 Port D Input Pullup Enable Register
- 16.7 Port E
- 16.7.1 Port E Data Register
- 16.7.2 Data Direction Register E
- Section 17. Random-Access Memory (RAM)
- Section 18. Serial Communications Interface Module (SCI)
- 18.1 Contents
- 18.2 Introduction
- 18.3 Features
- 18.4 Pin Name Conventions
- 18.5 Functional Description
- 18.5.1 Data Format
- 18.5.2 Transmitter
- 18.5.3 Receiver
- 18.6 Low-Power Modes
- 18.6.1 Wait Mode
- 18.6.2 Stop Mode
- 18.7 SCI During Break Module Interrupts
- 18.8 I/O Signals
- 18.8.1 PTE0/TxD (Transmit Data)
- 18.8.2 PTE1/RxD (Receive Data)
- 18.9 I/O Registers
- 18.9.1 SCI Control Register 1
- 18.9.2 SCI Control Register 2
- 18.9.3 SCI Control Register 3
- 18.9.4 SCI Status Register 1
- 18.9.5 SCI Status Register 2
- 18.9.6 SCI Data Register
- 18.9.7 SCI Baud Rate Register
- Section 19. System Integration Module (SIM)
- 19.1 Contents
- 19.2 Introduction
- 19.3 SIM Bus Clock Control and Generation
- 19.3.1 Bus Timing
- 19.3.2 Clock Startup from POR or LVI Reset
- 19.3.3 Clocks in Stop Mode and Wait Mode
- 19.4 Reset and System Initialization
- 19.4.1 External Pin Reset
- 19.4.2 Active Resets from Internal Sources
- 19.5 SIM Counter
- 19.5.1 SIM Counter During Power-On Reset
- 19.5.2 SIM Counter During Stop Mode Recovery
- 19.5.3 SIM Counter and Reset States
- 19.6 Exception Control
- 19.6.1 Interrupts
- 19.6.2 Reset
- 19.6.3 Break Interrupts
- 19.6.4 Status Flag Protection in Break Mode
- 19.7 Low-Power Modes
- 19.7.1 Wait Mode
- 19.7.2 Stop Mode
- 19.8 SIM Registers
- 19.8.1 SIM Break Status Register
- 19.8.2 SIM Reset Status Register
- 19.8.3 SIM Break Flag Control Register
- Section 20. Serial Peripheral Interface Module (SPI)
- 20.1 Contents
- 20.2 Introduction
- 20.3 Features
- 20.4 Pin Name Conventions and I/O Register Addresses
- 20.5 Functional Description
- 20.5.1 Master Mode
- 20.5.2 Slave Mode
- 20.6 Transmission Formats
- 20.6.1 Clock Phase and Polarity Controls
- 20.6.2 Transmission Format When CPHA = 0
- 20.6.3 Transmission Format When CPHA = 1
- 20.6.4 Transmission Initiation Latency
- 20.7 Queuing Transmission Data
- 20.8 Error Conditions
- 20.8.1 Overflow Error
- 20.8.2 Mode Fault Error
- 20.9 Interrupts
- 20.10 Resetting the SPI
- 20.11 Low-Power Modes
- 20.11.1 Wait Mode
- 20.11.2 Stop Mode
- 20.12 SPI During Break Interrupts
- 20.13 I/O Signals
- 20.13.1 MISO (Master In/Slave Out)
- 20.13.2 MOSI (Master Out/Slave In)
- 20.13.3 SPSCK (Serial Clock)
- 20.13.4 SS (Slave Select)
- 20.13.5 CGND (Clock Ground)
- 20.14 I/O Registers
- 20.14.1 SPI Control Register
- 20.14.2 SPI Status and Control Register
- 20.14.3 SPI Data Register
- Section 21. Timebase Module (TBM)
- Section 22. Timer Interface Module (TIM)
- 22.1 Contents
- 22.2 Introduction
- 22.3 Features
- 22.4 Pin Name Conventions
- 22.5 Functional Description
- 22.5.1 TIM Counter Prescaler
- 22.5.2 Input Capture
- 22.5.3 Output Compare
- 22.5.4 Unbuffered Output Compare
- 22.5.5 Buffered Output Compare
- 22.5.6 Pulse Width Modulation (PWM)
- 22.5.7 Unbuffered PWM Signal Generation
- 22.5.8 Buffered PWM Signal Generation
- 22.5.9 PWM Initialization
- 22.6 Interrupts
- 22.7 Low-Power Modes
- 22.7.1 Wait Mode
- 22.7.2 Stop Mode
- 22.8 TIM During Break Interrupts
- 22.9 I/O Signals
- 22.10 I/O Registers
- 22.10.1 TIM Status and Control Register
- 22.10.2 TIM Counter Registers
- 22.10.3 TIM Counter Modulo Registers
- 22.10.4 TIMA Counter Registers
- 22.10.5 TIM Channel Status and Control Registers
- 22.10.6 TIM Channel Registers
- Section 23. Preliminary Electrical Specifications
- 23.1 Contents
- 23.2 Introduction
- 23.3 Absolute Maximum Ratings
- 23.4 Functional Operating Range
- 23.5 Thermal Characteristics
- 23.6 5.0-V DC Electrical Characteristics
- 23.7 3.0-V DC Electrical Characteristics
- 23.8 5.0-V Control Timing
- 23.9 3.0-V Control Timing
- 23.10 Output High-Voltage Characteristics
- 23.11 Output Low-Voltage Characteristics
- 23.12 Typical Supply Currents
- 23.13 ADC Characteristics
- 23.14 5.0-V SPI Characteristics
- 23.15 3.0-V SPI Characteristics
- 23.16 Timer Interface Module Characteristics
- 23.17 Clock Generation Module Characteristics
- 23.17.1 CGM Component Specifications
- 23.17.2 CGM Electrical Specifications
- 23.18 Memory Characteristics
- Section 24. Mechanical Specifications
- Section 25. Ordering Information
Advance Information MC68HC908GP20 — Rev 2.1
194 Freescale Semiconductor
If the MODEK bit is set, the keyboard interrupt pins are both falling edge-
and low-level sensitive, and both of the following actions must occur to
clear a keyboard interrupt request:
• Vector fetch or software clear — A vector fetch generates an
interrupt acknowledge signal to clear the interrupt request.
Software may generate the interrupt acknowledge signal by
writing a logic 1 to the ACKK bit in the keyboard status and control
register (INTKBSCR). The ACKK bit is useful in applications that
poll the keyboard interrupt pins and require software to clear the
keyboard interrupt request. Writing to the ACKK bit prior to leaving
an interrupt service routine can also prevent spurious interrupts
due to noise. Setting ACKK does not affect subsequent transitions
on the keyboard interrupt pins. A falling edge that occurs after
writing to the ACKK bit latches another interrupt request. If the
keyboard interrupt mask bit, IMASKK, is clear, the CPU loads the
program counter with the vector address at locations $FFE0 and
$FFE1.
• Return of all enabled keyboard interrupt pins to logic 1 — As long
as any enabled keyboard interrupt pin is at logic 0, the keyboard
interrupt remains set.
The vector fetch or software clear and the return of all enabled keyboard
interrupt pins to logic 1 may occur in any order.
If the MODEK bit is clear, the keyboard interrupt pin is falling-edge-
sensitive only. With MODEK clear, a vector fetch or software clear
immediately clears the keyboard interrupt request.
Reset clears the keyboard interrupt request and the MODEK bit, clearing
the interrupt request even if a keyboard interrupt pin stays at logic 0.
The keyboard flag bit (KEYF) in the keyboard status and control register
can be used to see if a pending interrupt exists. The KEYF bit is not
affected by the keyboard interrupt mask bit (IMASKK) which makes it
useful in applications where polling is preferred.
To determine the logic level on a keyboard interrupt pin, use the data
direction register to configure the pin as an input and read the data
register.