iv
6.9 Clock Oscillator Circuits .................................................................................................................... 76
6.10 Overview of Prescaler ....................................................................................................................... 78
6.11 Configuration of Prescaler ................................................................................................................ 79
6.12 Operating Explanation of Prescaler .................................................................................................. 80
6.13 Notes on Use of Prescaler ................................................................................................................ 81
CHAPTER 7 RESET ........................................................................................................ 83
7.1 Reset Operation ................................................................................................................................ 84
7.2 Reset Source Register (RSRR) ........................................................................................................ 88
CHAPTER 8 INTERRUPTS ............................................................................................. 91
8.1 Interrupts ........................................................................................................................................... 92
8.1.1 Interrupt Level Setting Registers (ILR0 to ILR5) .......................................................................... 94
8.1.2 Interrupt Processing .................................................................................................................... 95
8.1.3 Nested Interrupts ......................................................................................................................... 97
8.1.4 Interrupt Processing Time ........................................................................................................... 98
8.1.5 Stack Operations During Interrupt Processing ............................................................................ 99
8.1.6 Interrupt Processing Stack Area ................................................................................................ 100
CHAPTER 9 I/O PORT .................................................................................................. 101
9.1 Overview of I/O Ports ...................................................................................................................... 102
9.2 Port 0 .............................................................................................................................................. 104
9.2.1 Port 0 Registers ......................................................................................................................... 106
9.2.2 Operations of Port 0 .................................................................................................................. 107
9.3 Port 1 .............................................................................................................................................. 109
9.3.1 Port 1 Registers ......................................................................................................................... 112
9.3.2 Operations of Port 1 .................................................................................................................. 113
9.4 Port 4 .............................................................................................................................................. 115
9.4.1 Port 4 Registers ......................................................................................................................... 117
9.4.2 Operations of Port 4 .................................................................................................................. 118
9.5 Port 5 .............................................................................................................................................. 120
9.5.1 Port 5 Registers ......................................................................................................................... 122
9.5.2 Operations of Port 5 .................................................................................................................. 123
9.6 Port 6 .............................................................................................................................................. 125
9.6.1 Port 6 Registers ......................................................................................................................... 127
9.6.2 Operations of Port 6 .................................................................................................................. 128
9.7 Port 9 .............................................................................................................................................. 130
9.7.1 Port 9 Registers ......................................................................................................................... 132
9.7.2 Operations of Port 9 .................................................................................................................. 133
9.8 Port A .............................................................................................................................................. 135
9.8.1 Port A Registers ........................................................................................................................ 137
9.8.2 Operations of Port A .................................................................................................................. 138
9.9 Port B .............................................................................................................................................. 140
9.9.1 Port B Registers ........................................................................................................................ 142
9.9.2 Operations of Port B .................................................................................................................. 143
9.10 Port C .............................................................................................................................................. 145
9.10.1 Port C Registers ........................................................................................................................ 147