C8051F97X View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

Manufacturer

C8051F97X

Low Power Capacitive Sensing MCU with up to 32 kB of Flash

Silicon Laboratories 

24.4.Special Function Registers for Selecting and Configuring the System Clock............ 246

24.5.Clock Selection Control Registers ............................................................................. 247

24.6.High Frequency Oscillator Registers ......................................................................... 250

24.7.External Oscillator Registers...................................................................................... 252

25. SmaRTClock (Real Time Clock, RTC0) ..........................................................................253

25.1.SmaRTClock Interface...............................................................................................254

25.1.1.Using RTC0ADR and RTC0DAT to Access SmaRTClock Internal Registers... 254

25.1.2.RTC0ADR Short Strobe Feature ....................................................................... 254

25.1.3.SmaRTClock Interface Autoread Feature ......................................................... 255

25.1.4.RTC0ADR Autoincrement Feature .................................................................... 255

25.2.SmaRTClock Clocking Sources.................................................................................256

25.2.1.Using the SmaRTClock Oscillator with a Crystal............................................... 256

25.2.2.Using the SmaRTClock Oscillator in Self-Oscillate Mode ................................. 257

25.2.3.Using the Low Frequency Oscillator (LFO) ....................................................... 257

25.2.4.Programmable Load Capacitance ..................................................................... 258

25.2.5.Automatic Gain Control (Crystal Mode Only) and SmaRTClock Bias Doubling 259

25.2.6.Missing SmaRTClock Detector..........................................................................261

25.2.7.SmaRTClock Oscillator Crystal Valid Detector.................................................. 261

25.3.SmaRTClock Timer and Alarm Function ...................................................................261

25.3.1.Setting and Reading the SmaRTClock Timer Value ......................................... 261

25.3.2.Setting a SmaRTClock Alarm............................................................................ 262

25.3.3.Software Considerations for Using the SmaRTClock Timer and Alarm ............ 263

25.4.RTC0 Control Registers............................................................................................. 264

26. Port I/O (Port 0, Port 1, Port 2, Port 3, Port 4, Port 5, Port 6, Crossbar, and Port Match)

277

26.1.General Port I/O Initialization ..................................................................................... 278

26.2.Assigning Port I/O Pins to Analog and Digital Functions ........................................... 279

26.2.1.Assigning Port I/O Pins to Analog Functions.....................................................279

26.2.2.Assigning Port I/O Pins to Digital Functions ...................................................... 280

26.2.3.Assigning Port I/O Pins to Fixed Digital Functions ............................................ 280

26.3.Priority Crossbar Decoder.......................................................................................... 281

26.4.Port I/O Modes of Operation ...................................................................................... 283

26.4.1.Configuring Port Pins For Analog Modes .......................................................... 283

26.4.2.Configuring Port Pins For Digital Modes ........................................................... 283

26.4.3.Port Drive Strength ............................................................................................ 283

26.5.Port Match.................................................................................................................. 284

26.6.Direct Read/Write Access to Port I/O Pins................................................................. 284

26.7.Port Configuration Registers...................................................................................... 285

26.8.Port I/O Control Registers.......................................................................................... 287

27. Reset Sources and Supply Monitor ............................................................................... 322

27.1.Power-On Reset ........................................................................................................ 323

27.2.Power-Fail Reset / Supply Monitor ............................................................................ 324

27.3.Enabling the VDD Monitor ......................................................................................... 325

27.4.External Reset ........................................................................................................... 325

27.5.Missing Clock Detector Reset.................................................................................... 325

27.6.PCA Watchdog Timer Reset...................................................................................... 325

Rev 1.1

6

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