Contents
Status Register - STATUS ...................................................................................20
Input/Output Ports and Control Registers .............................................................21
System Control Registers - CTRL0, CTRL1.........................................................22
REMAP Register ..................................................................................................23
Wake-up Function Register - PAWK ....................................................................24
Pull-high Registers - PAPU, PBPU, PCPU, PDPU ...............................................24
Software COM Register - SCOMC.......................................................................24
Oscillator............................................................................................25
System Oscillator Overview..................................................................................25
System Clock Configurations................................................................................25
External Crystal/Resonator Oscillator - HXT ........................................................25
External RC Oscillator - ERC ...............................................................................26
Internal RC Oscillator - HIRC ...............................................................................26
External 32768Hz Crystal Oscillator - LXT ...........................................................27
LXT Oscillator Low Power Function ......................................................................27
Internal Low Speed Oscillator - LIRC ...................................................................28
Operating Modes ...............................................................................28
Mode Types and Selection ...................................................................................28
Mode Switching ....................................................................................................29
Standby Current Considerations...........................................................................29
Wake-up ...............................................................................................................30
Watchdog Timer ................................................................................31
Watchdog Timer Operation...................................................................................31
Reset and Initialisation .....................................................................33
Reset Functions ...................................................................................................33
Reset Initial Conditions .........................................................................................35
Input/Output Ports.............................................................................38
Pull-high Resistors................................................................................................38
Port A Wake-up ....................................................................................................38
I/O Port Control Registers.....................................................................................40
Pin-shared Functions............................................................................................40
I/O Pin Structures .................................................................................................41
Programming Considerations ...............................................................................41
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