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CONTENTS

CHAPTER 1 OVERVIEW ................................................................................................... 1

1.1 MB91F109 Characteristics ..................................................................... ............................................... 2
1.2 General Block Diagram of MB91F109 ................................................................................................... 6
1.3 Outside Dimensions ................................................................................ ............................................... 7
1.4 Pin Arrangement Diagrams ............................................................. .................................................... 10
1.5 Pin Functions ................................ ................................................................................................. ...... 14
1.6 I/O Circuit Format ................................................................................... ............................................. 22
1.7 Memory Address Space ...................................................................................... ...... ....... .... .. ............. 24
1.8 Handling of Devices ......................................... .................................................................................... 26

CHAPTER 2 CPU ............................................................................................................. 29

2.1 CPU Architecture ....................................... .......................................................................................... 30
2.2 Internal Architecture ............................................................................................. ...... ... .... ................... 31
2.3 Programming Model ............................................................................... ...... ....... ...... ....... . ..... ............. 33
2.3.1 General-Purpose Registers ........................................................ .................................................... 35
2.3.2 Special Registers ............................................................................................................................ 36
2.3.3 Program Status Register (PS) .................................................... .................................................... 39
2.4 Data Structure ......................................................................................... ............................................. 42
2.5 Word Alignment ......................................................................................................... .......................... 43
2.6 Memory Map ....................................................................... ....... ...... ....... ...... ....... ...... ... .... ................... 44
2.7 Instruction Overview ............................................................................................ ................................ 46
2.7.1 Branch Instructions with Delay Slots .......... .................................................................................... 48
2.7.2 Branch Instructions without Delay Slots ............ ............................................................................. 51
2.8 EIT (Exception, Interrupt, and Trap) ....................................................................................... ............. 52
2.8.1 EIT Interrupt Levels .................................................................... ....... ............................................. 54
2.8.2 Interrupt Control Register (ICR) ...................................................................................................... 56
2.8.3 System Stack Pointer (SSP) ........................................................................................................... 57
2.8.4 Interrupt Stack ................................................... ............................................................................. 58
2.8.5 Table Base Register (TBR) ..... ....................................................................................................... 59
2.8.6 EIT Vector Table ............................................................................................................................. 60
2.8.7 Multiple EIT Processing ........................................................................................ .......................... 62
2.8.8 EIT Operation ................................................................ ....... ...... ....... ...... ....... ...... ..... ..................... 64
2.9 Reset Sequence ........................................................................................................ .......................... 68
2.10 Operation Mode ......................................... ...... ....... ...... ...... ....... ...... ....... ............................................. 69

CHAPTER 3 CLOCK GENERATOR AND CONTROLLER ............................................. 73

3.1 Outline of Clock Generator and Controller .............................................. ............................................. 74
3.2 Reset Reason Resister (RSRR) and Watchdog Cycle Control Register (WTCR) ............................... 76
3.3 Standby Control Register (STCR) .......................................................... ............................................. 78
3.4 DMA Request Suppression Register (PDRR) ........................................ ............................................. 80
3.5 Timebase Timer Clear Register (CTBR) .............................................................. ................................ 81
3.6 Gear Control Register (GCR) ................................................................. ............................................. 82
3.7 Watchdog Timer Reset Delay Register (WPR) ............................................. ....................................... 85
3.8 PLL Control Register (PCTR) ................................................................................................ .............. 86