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Philips Semiconductors
1. General Description................................................................................... 9
Pin configuration...................................................................................................... 9
20-Pin TSSOP, DIP Package .................................................................................. 9
Logic symbol............................................................................................................ 9
Pin Descriptions....................................................................................................... 11
Special Function Registers...................................................................................... 14
Memory organization ............................................................................................... 18
Data RAM arrangement................................................................................ 19
2. Clocks........................................................................................................ 21
Enhanced CPU........................................................................................................ 21
Clocks...................................................................................................................... 21
Clock definitions ...................................................................................................... 21
Oscillator clock (OSCCLK) ........................................................................... 21
Low speed oscillator option .......................................................................... 21
Medium speed oscillator option .................................................................... 21
High speed oscillator option.......................................................................... 21
Clock output............................................................................................................. 21
On-chip RC oscillator option.................................................................................... 22
Watchdog oscillator option ...................................................................................... 22
External clock input option....................................................................................... 23
Oscillator Clock (OSCCLK) wakeup delay .............................................................. 23
CPU Clock (CCLK) modification: DIVM register...................................................... 23
Low power select..................................................................................................... 24
3. Interrupts ................................................................................................... 25
Interrupt priority structure ........................................................................................ 25
External Interrupt pin glitch suppression ................................................................. 26
4. I/O Ports .................................................................................................... 29
Port configurations................................................................................................... 29
Quasi-bidirectional output configuration .................................................................. 29
Open drain output configuration .............................................................................. 30
Input-only configuration ........................................................................................... 31
Push-pull output configuration ................................................................................. 31
Port 0 analog functions............................................................................................ 31
Additional port features............................................................................................ 32
5. Power Monitoring Functions ...................................................................... 33
Brownout Detection ................................................................................................. 33
Power-on Detection ................................................................................................. 34
Power reduction modes........................................................................................... 34
6. Reset ......................................................................................................... 39
Reset vector ............................................................................................................ 40
7. Timers 0 and 1........................................................................................... 41
2003 Dec 8
Table of Contents
3
User Manual - Subject to Change
P89LPC920/921/922
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