Contents
Special Purpose Data Memory.........................................................20
Special Function Registers...................................................................................20
Indirect Addressing Registers - IAR0, IAR1 .........................................................20
Memory Pointers - MP0, MP1..............................................................................20
Accumulator - ACC..............................................................................................22
Program Counter Low Register - PCL..................................................................22
Status Register - STATUS ...................................................................................22
Input/Output Ports and Control Registers .............................................................23
System Control Registers - CTRL0, CTRL1.........................................................24
REMAP Register ..................................................................................................25
Wake-up Function Register - PAWK ....................................................................26
Pull-high Registers - PAPU, PBPU, PCPU, PDPU...............................................26
Software COM Register - SCOMC.......................................................................26
Oscillator............................................................................................27
System Oscillator Overview..................................................................................27
System Clock Configurations................................................................................27
External Crystal/Resonator Oscillator - HXT ........................................................27
External RC Oscillator - ERC...............................................................................28
Internal RC Oscillator - HIRC...............................................................................28
External 32768Hz Crystal Oscillator - LXT...........................................................29
LXT Oscillator Low Power Function......................................................................29
Internal Low Speed Oscillator - LIRC...................................................................30
Operating Modes...............................................................................30
Mode Types and Selection ...................................................................................30
Mode Switching....................................................................................................31
Standby Current Considerations...........................................................................31
Wake-up...............................................................................................................32
Watchdog Timer ................................................................................33
Watchdog Timer Operation...................................................................................33
Reset and Initialisation .....................................................................35
Reset Functions ...................................................................................................35
Reset Initial Conditions.........................................................................................37
Input/Output Ports.............................................................................40
Pull-high Resistors................................................................................................40
Port A Wake-up ....................................................................................................40
I/O Port Control Registers.....................................................................................42
Pin-shared Functions............................................................................................42
I/O Pin Structures .................................................................................................43
Programming Considerations ...............................................................................43
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