Holtek HT66F20 Manual page 3

HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
EEPROM Data Memory .................................................................................. 44
EEPROM Data Memory Str�ct�re ........................................................................................ 44
EEPROM Registers .............................................................................................................. 44
Reading Data from the EEPROM ......................................................................................... 48
Writing Data to the EEPROM ................................................................................................ 48
Write Protection ..................................................................................................................... 48
EEPROM Interr�pt ................................................................................................................ 48
Programming Considerations ................................................................................................ 49
Programming Examples ........................................................................................................ 49
Oscillators ...................................................................................................... 50
Oscillator Overview ............................................................................................................... 50
System Clock Configurations ................................................................................................ 50
External Crystal/Ceramic Oscillator - HXT ........................................................................... 52
External RC Oscillator - ERC ............................................................................................... 53
Internal High Speed RC Oscillator - HIRC ........................................................................... 53
External 32.�68kHz Crystal Oscillator - LXT ........................................................................ 54
Internal Low Speed Oscillator - LIRC ................................................................................... 55
S�pplementary Oscillators .................................................................................................... 55
Operating Modes and System Clocks ......................................................... 56
System Clock ........................................................................................................................ 56
System Operation Modes ...................................................................................................... 58
Control Register .................................................................................................................... 59
Fast Wake-�p ........................................................................................................................ 6�
Operating Mode Switching .................................................................................................... 62
Standby C�rrent Considerations ........................................................................................... 66
Wake-�p ................................................................................................................................ 6�
Programming Considerations ................................................................................................ 6�
Watchdog Timer ............................................................................................. 68
Watchdog Timer Clock So�rce .............................................................................................. 68
Watchdog Timer Control Register ......................................................................................... 68
Watchdog Timer Operation ................................................................................................... 69
Reset and Initialisation .................................................................................. 70
Reset F�nctions .................................................................................................................... �0
Reset Initial Conditions ......................................................................................................... �3
Input/Output Ports ......................................................................................... 83
P�ll-high Resistors ................................................................................................................ 86
Port A Wake-�p ..................................................................................................................... 88
I/O Port Control Registers ..................................................................................................... 88
Pin-remapping F�nctions ...................................................................................................... 9�
Pin-remapping Registers ....................................................................................................... 9�
I/O Pin Str�ct�res .................................................................................................................. 98
Programming Considerations ................................................................................................ 99
Rev. 2.50 3 ��ne 22� 20��