![](http://datasheet.mmic.net.cn/Renesas-Electronics-America/UPD78F1188AGJ-GAE-AX_datasheet_99859/UPD78F1188AGJ-GAE-AX_12.png)
User’s Manual U18417EJ4V0UD
10
4.2.15 Port 14...........................................................................................................................................156
4.2.16 Port 15...........................................................................................................................................161
4.2.17 Port 16...........................................................................................................................................162
4.3 Registers Controlling Port Function.................................................................................................. 163
4.4 Port Function Operations.................................................................................................................... 172
4.4.1 Writing to I/O port ............................................................................................................................172
4.4.2 Reading from I/O port......................................................................................................................172
4.4.3 Operations on I/O port.....................................................................................................................172
4.4.4 Connecting to external device with different power potential (2.5 V, 3 V)........................................173
4.5 Settings of Port Mode Register and Output Latch When Using Alternate Function .................. 175
4.6 Cautions on 1-Bit Manipulation Instruction for Port Register n (Pn) ............................................ 179
CHAPTER 5 EXTERNAL BUS INTERFACE ...................................................................................... 180
5.1 Functions of External Bus Interface .................................................................................................. 180
5.2 Registers Controlling External Bus Interface Functions................................................................ 185
5.3 Setting Port Mode Register and Output Latch ................................................................................. 188
5.4 Number of Instruction Wait Clocks or Data Access........................................................................ 189
5.5 Number of Instruction Execution Clocks and Instruction Wait Clocks for Fetch Access......... 189
5.6 Number of Instructed Wait Cycles According to External Wait Cycles........................................ 190
5.7 Timing of External Bus Interface Function ....................................................................................... 191
5.7.1 Multiplexed bus mode .....................................................................................................................192
5.7.2 Separate bus mode .........................................................................................................................196
5.8 Example of Connection to Memory ................................................................................................... 200
5.8.1 Connection of external logic (ASIC, etc.).........................................................................................200
5.8.2 Connection of synchronous memory ...............................................................................................200
5.8.3 Connection of asynchronous memory .............................................................................................201
CHAPTER 6 CLOCK GENERATOR .................................................................................................... 202
6.1 Functions of Clock Generator ............................................................................................................ 202
6.2 Configuration of Clock Generator...................................................................................................... 203
6.3 Registers Controlling Clock Generator ............................................................................................. 205
6.4 System Clock Oscillator ...................................................................................................................... 219
6.4.1 X1 oscillator.....................................................................................................................................219
6.4.2 XT1 oscillator ..................................................................................................................................219
6.4.3 Internal high-speed oscillator ..........................................................................................................222
6.4.4 Internal low-speed oscillator............................................................................................................222
6.4.5 Prescaler .........................................................................................................................................222
6.5 Clock Generator Operation ................................................................................................................. 223
6.6 Controlling Clock.................................................................................................................................. 227
6.6.1 Example of controlling high-speed system clock .............................................................................227
6.6.2 Example of controlling internal high-speed oscillation clock............................................................230
6.6.3 Example of controlling subsystem clock..........................................................................................232
6.6.4 Example of controlling internal low-speed oscillation clock .............................................................234
6.6.5 CPU clock status transition diagram................................................................................................235
6.6.6 Condition before changing CPU clock and processing after changing CPU clock ..........................240
6.6.7 Time required for switchover of CPU clock and main system clock ................................................242
6.6.8 Conditions before clock oscillation is stopped .................................................................................243