A - 5

20.4.3

EW0 Mode ........................................................................................................................................ 255

20.4.4

EW1 Mode ........................................................................................................................................ 261

20.5

Standard Serial I/O Mode ...................................................................................................................... 266

20.5.1

ID Code Check Function .................................................................................................................. 266

20.6

Parallel I/O Mode .................................................................................................................................. 268

20.6.1

ROM Code Protect Function ............................................................................................................ 268

20.7

Notes on Flash Memory ........................................................................................................................ 269

20.7.1

CPU Rewrite Mode ........................................................................................................................... 269

21.

Reducing Power Consumption ................................................................................................... 271

21.1

Overview ............................................................................................................................................... 271

21.2

Key Points and Processing Methods for Reducing Power Consumption ............................................. 271

21.2.1

Voltage Detection Circuit ................................................................................................................. 271

21.2.2

Ports .................................................................................................................................................. 271

21.2.3

Clocks ............................................................................................................................................... 271

21.2.4

Selecting Oscillation Drive Capacity ................................................................................................ 271

21.2.5

Wait Mode, Stop Mode ..................................................................................................................... 271

21.2.6

Stopping Peripheral Function Clocks ............................................................................................... 271

21.2.7

Timers ............................................................................................................................................... 271

21.2.8

Reducing Internal Power Consumption ............................................................................................ 272

21.2.9

Stopping Flash Memory .................................................................................................................... 273

21.2.10

Low-Current-Consumption Read Mode ........................................................................................... 274

22.

Electrical Characteristics ............................................................................................................ 275

23.

Usage Notes ............................................................................................................................... 292

23.1

Notes on I/O Ports ................................................................................................................................. 292

23.1.1

Port P4_3, P4_4 ................................................................................................................................ 292

23.2

Notes on Clock Generation Circuit ....................................................................................................... 293

23.2.1

Stop Mode ......................................................................................................................................... 293

23.2.2

Wait Mode ........................................................................................................................................ 293

23.2.3

Oscillation Circuit Constants ............................................................................................................ 293

23.3

Notes on Interrupts ................................................................................................................................ 294

23.3.1

Reading Address 00000h .................................................................................................................. 294

23.3.2

SP Setting .......................................................................................................................................... 294

23.3.3

External Interrupt and Key Input Interrupt ....................................................................................... 294

23.3.4

Changing Interrupt Sources .............................................................................................................. 295

23.3.5

Changing Interrupt Control Register Contents ................................................................................. 296

23.4

Notes on ID Code Areas ........................................................................................................................ 297

23.4.1

Setting Example of ID Code Areas ................................................................................................... 297

23.5

Notes on Option Function Select Area .................................................................................................. 298

23.5.1

Setting Example of Option Function Select Area ............................................................................. 298

23.6

Notes on Timers .................................................................................................................................... 299

23.6.1

Notes on Timer RA ........................................................................................................................... 299

23.6.2

Notes on Timer RB ........................................................................................................................... 300

23.6.3

Notes on Timer RE ........................................................................................................................... 304

23.6.4

Notes on Timer RF ........................................................................................................................... 307

23.7

Notes on Serial Interface ....................................................................................................................... 308

23.8

Notes on Hardware LIN ........................................................................................................................ 309