Datasheet

ManualsBrandsNXP SEMICONDUCTORS ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller QFP 64 (14x14) 8-Bit 8 MHz I/O number 51

100

Table Of Contents

List of Sections
Table of Contents
List of Figures
List of Tables
Section 1. General Description
- 1.1 Contents
- 1.2 Introduction
- 1.3 Features
- 1.4 MCU Block Diagram
- 1.5 Pin Assignments
- 1.6 Pin Functions
- 1.7 I/O Pin Summary
- 1.8 Signal Name Conventions
- 1.9 Clock Source Summary
Section 2. Memory Map
- 2.1 Contents
- 2.2 Introduction
- 2.3 Unimplemented Memory Locations
- 2.4 Reserved Memory Locations
- 2.5 Input/Output (I/O) Section
Section 3. Random-Access Memory (RAM)
- 3.1 Contents
- 3.2 Introduction
- 3.3 Functional Description
Section 4. FLASH Memory
- 4.1 Contents
- 4.2 Introduction
- 4.3 Functional Description
- 4.4 FLASH Control Register
- 4.5 FLASH Page Erase Operation
- 4.6 FLASH Mass Erase Operation
- 4.7 FLASH Program/Read Operation
- 4.8 FLASH Block Protection
  - 4.8.1 FLASH Block Protect Register
- 4.9 Wait Mode
- 4.10 Stop Mode
Section 5. EEPROM
- 5.1 Contents
- 5.2 Introduction
- 5.3 Features
- 5.4 Functional Description
- 5.5 EEPROM Configuration
- 5.6 EEPROM Timebase Requirements
- 5.7 EEPROM Security Options
- 5.8 EEPROM Block Protection
- 5.9 EEPROM Programming and Erasing
  - 5.9.1 EEPROM Programming
  - 5.9.2 EEPROM Erasing
- 5.10 Low Power Modes
  - 5.10.1 Wait Mode
  - 5.10.2 Stop Mode
- 5.11 EEPROM Registers
Section 6. Configuration Register (CONFIG)
- 6.1 Contents
- 6.2 Introduction
- 6.3 Functional description
- 6.4 Configuration Register 1
- 6.5 Configuration Register 2
Section 7. Central Processor Unit (CPU)
- 7.1 Contents
- 7.2 Introduction
- 7.3 Features
- 7.4 CPU Registers
- 7.5 Arithmetic/Logic Unit (ALU)
- 7.6 Low-Power Modes
  - 7.6.1 Wait Mode
  - 7.6.2 Stop Mode
- 7.7 CPU During Break Interrupts
- 7.8 Instruction Set Summary
- 7.9 Opcode Map
Section 8. System Integration Module (SIM)
- 8.1 Contents
- 8.2 Introduction
- 8.3 SIM Bus Clock Control and Generation
- 8.4 Reset and System Initialization
  - 8.4.1 External Pin Reset
  - 8.4.2 Active Resets from Internal Sources
- 8.5 SIM Counter
- 8.6 Exception Control
- 8.7 Low-Power Modes
  - 8.7.1 Wait Mode
  - 8.7.2 Stop Mode
- 8.8 SIM Registers
Section 9. Clock Generator Module (CGM)
- 9.1 Contents
- 9.2 Introduction
- 9.3 Features
- 9.4 Functional Description
- 9.5 I/O Signals
- 9.6 CGM Registers
- 9.7 Interrupts
- 9.8 Low-Power Modes
  - 9.8.1 Wait Mode
  - 9.8.2 Stop Mode
- 9.9 CGM During Break Interrupts
- 9.10 Acquisition/Lock Time Specifications
Section 10. Monitor ROM (MON)
- 10.1 Contents
- 10.2 Introduction
- 10.3 Features
- 10.4 Functional Description
- 10.5 Security
- 10.6 Extended Security
Section 11. Timer Interface Module A (TIMA)
- 11.1 Contents
- 11.2 Introduction
- 11.3 Features
- 11.4 Pin Name Conventions
- 11.5 Functional Description
- 11.6 Interrupts
- 11.7 Low-Power Modes
  - 11.7.1 Wait Mode
  - 11.7.2 Stop Mode
- 11.8 TIMA During Break Interrupts
- 11.9 I/O Signals
  - 11.9.1 TIMA Clock Pin
  - 11.9.2 TIMA Channel I/O Pins
- 11.10 I/O Registers
Section 12. Timer Interface Module B (TIMB)
- 12.1 Contents
- 12.2 Introduction
- 12.3 Features
- 12.4 Pin Name Conventions
- 12.5 Functional Description
- 12.6 Interrupts
- 12.7 Low-Power Modes
  - 12.7.1 Wait Mode
  - 12.7.2 Stop Mode
- 12.8 TIMB During Break Interrupts
- 12.9 I/O Signals
  - 12.9.1 TIMB Clock Pin
  - 12.9.2 TIMB Channel I/O Pins
- 12.10 I/O Registers
Section 13. Programmable Interrupt Timer (PIT)
- 13.1 Contents
- 13.2 Introduction
- 13.3 Features
- 13.4 Functional Description
  - 13.4.1 PIT Counter Prescaler
- 13.5 Low-Power Modes
  - 13.5.1 Wait Mode
  - 13.5.2 Stop Mode
- 13.6 PIT During Break Interrupts
- 13.7 I/O Registers
Section 14. Analog-to-Digital Converter (ADC)
- 14.1 Contents
- 14.2 Introduction
- 14.3 Features
- 14.4 Functional Description
- 14.5 Interrupts
- 14.6 Low-Power Modes
  - 14.6.1 Wait Mode
  - 14.6.2 Stop Mode
- 14.7 I/O Signals
- 14.8 I/O Registers
Section 15. Serial Communications Interface Module (SCI)
- 15.1 Contents
- 15.2 Introduction
- 15.3 Features
- 15.4 Pin Name Conventions
- 15.5 Functional Description
- 15.6 Low-Power Modes
  - 15.6.1 Wait Mode
  - 15.6.2 Stop Mode
- 15.7 SCI During Break Module Interrupts
- 15.8 I/O Signals
  - 15.8.1 PTE0/TxD (Transmit Data)
  - 15.8.2 PTE1/RxD (Receive Data)
- 15.9 I/O Registers
Section 16. Serial Peripheral Interface Module (SPI)
- 16.1 Contents
- 16.2 Introduction
- 16.3 Features
- 16.4 Pin Name Conventions and I/O Register Addresses
- 16.5 Functional Description
  - 16.5.1 Master Mode
  - 16.5.2 Slave Mode
- 16.6 Transmission Formats
- 16.7 Queuing Transmission Data
- 16.8 Error Conditions
  - 16.8.1 Overflow Error
  - 16.8.2 Mode Fault Error
- 16.9 Interrupts
- 16.10 Resetting the SPI
- 16.11 Low-Power Modes
  - 16.11.1 Wait Mode
  - 16.11.2 Stop Mode
- 16.12 SPI During Break Interrupts
- 16.13 I/O Signals
- 16.14 I/O Registers
Section 17. Input/Output (I/O) Ports
- 17.1 Contents
- 17.2 Introduction
- 17.3 Port A
  - 17.3.1 Port A Data Register (PTA)
  - 17.3.2 Data Direction Register A (DDRA)
- 17.4 Port B
  - 17.4.1 Port B Data Register (PTB)
  - 17.4.2 Data Direction Register B (DDRB)
- 17.5 Port C
  - 17.5.1 Port C Data Register (PTC)
  - 17.5.2 Data Direction Register C (DDRC)
- 17.6 Port D
- 17.7 Port E
  - 17.7.1 Port E Data Register (PTE)
  - 17.7.2 Data Direction Register E (DDRE)
- 17.8 Port F
- 17.9 Port G
  - 17.9.1 Port G Data Register (PTG)
  - 17.9.2 Data Direction Register G (DDRG)
- 17.10 Port H
  - 17.10.1 Port H Data Register (PTH)
  - 17.10.2 Data Direction Register H (DDRH)
Section 18. External Interrupt (IRQ)
- 18.1 Contents
- 18.2 Introduction
- 18.3 Features
- 18.4 Functional Description
  - 18.4.1 IRQ Pin
- 18.5 IRQ Status and Control Register (ISCR)
- 18.6 IRQ Module During Break Interrupts
Section 19. Keyboard Interrupt Module (KBI)
- 19.1 Contents
- 19.2 Introduction
- 19.3 Features
- 19.4 I/O Pins
- 19.5 Functional Description
- 19.6 Wait Mode
- 19.7 Stop Mode
- 19.8 Keyboard Module During Break Interrupts
Section 20. Computer Operating Properly (COP)
- 20.1 Contents
- 20.2 Introduction
- 20.3 Functional Description
- 20.4 I/O Signals
- 20.5 COP Control Register
- 20.6 Interrupts
- 20.7 Monitor Mode
- 20.8 Low-Power Modes
  - 20.8.1 Wait Mode
  - 20.8.2 Stop Mode
- 20.9 COP Module During Break Mode
Section 21. Low-Voltage Inhibit (LVI)
- 21.1 Contents
- 21.2 Introduction
- 21.3 Features
- 21.4 Functional Description
- 21.5 LVI Status Register (LVISR)
- 21.6 LVI Interrupts
- 21.7 Low-Power Modes
  - 21.7.1 Wait Mode
  - 21.7.2 Stop Mode
Section 22. Break Module (BRK)
- 22.1 Contents
- 22.2 Introduction
- 22.3 Features
- 22.4 Functional Description
- 22.5 Low-Power Modes
  - 22.5.1 Wait Mode
  - 22.5.2 Stop Mode
- 22.6 Break Module Registers
Section 23. 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 EEPROM and Memory Characteristics
- 23.8 5.0-V Control Timing
- 23.9 Timer Interface Module Characteristics
- 23.10 ADC Characteristics
- 23.11 SPI Characteristics
- 23.12 Clock Generation Module Characteristics
- 23.13 FLASH Memory Characteristics
Section 24. Mechanical Specifications
- 24.1 Contents
- 24.2 Introduction
- 24.3 64-Pin Plastic Quad Flat Pack (QFP)
Section 25. Ordering Information
- 25.1 Contents
- 25.2 Introduction
- 25.3 MC Order Numbers

Central Processor Unit (CPU)

Technical Data MC68HC908AB32 — Rev. 1.1

92 Central Processor Unit (CPU) Freescale Semiconductor

7.4.2 Index Register

The 16-bit index register allows indexed addressing of a 64K-byte

memory space. H is the upper byte of the index register, and X is the

lower byte. H:X is the concatenated 16-bit index register.

In the indexed addressing modes, the CPU uses the contents of the

index register to determine the conditional address of the operand.

The index register can serve also as a temporary data storage location.

7.4.3 Stack Pointer

The stack pointer is a 16-bit register that contains the address of the next

location on the stack. During a reset, the stack pointer is preset to

$00FF. The reset stack pointer (RSP) instruction sets the least

significant byte to $FF and does not affect the most significant byte. The

stack pointer decrements as data is pushed onto the stack and

increments as data is pulled from the stack.

In the stack pointer 8-bit offset and 16-bit offset addressing modes, the

stack pointer can function as an index register to access data on the

stack. The CPU uses the contents of the stack pointer to determine the

conditional address of the operand.

Bit

1413121110987654321

Bit

Read:

Write:

Reset:00000000XXXXXXXX

X = Indeterminate

Figure 7-3. Index Register (H:X)