Datasheet

ii
4127H–8051–02/08
A/T89C51AC2
Registers............................................................................................................. 43
Operation Cross Memory Access ..................................................... 44
Sharing Instructions........................................................................... 45
In-System Programming (ISP)........................................................... 47
Flash Programming and Erasure........................................................................ 47
Boot Process ...................................................................................................... 48
Application Programming Interface..................................................................... 49
XROW Bytes....................................................................................................... 49
Hardware Security Byte ...................................................................................... 50
Serial I/O Port...................................................................................... 51
Framing Error Detection .................................................................................... 51
Automatic Address Recognition.......................................................................... 52
Given Address .................................................................................................... 53
Broadcast Address ............................................................................................. 53
Registers............................................................................................................. 54
Timers/Counters ................................................................................. 57
Timer/Counter Operations .................................................................................. 57
Timer 0................................................................................................................ 57
Timer 1................................................................................................................ 60
Interrupt .............................................................................................................. 60
Registers............................................................................................................. 62
Timer 2................................................................................................. 66
Auto-Reload Mode............................................................................................. 66
Programmable Clock-Output .............................................................................. 67
Registers............................................................................................................. 68
Watchdog Timer ................................................................................. 71
Watchdog Programming ..................................................................................... 72
Watchdog Timer During Power-down Mode and Idle ......................................... 73
Programmable Counter Array (PCA) ................................................ 75
PCA Timer .......................................................................................................... 75
PCA Modules...................................................................................................... 76
PCA Interrupt...................................................................................................... 77
PCA Capture Mode............................................................................................. 77
16-bit Software Timer Mode ............................................................................... 78
High Speed Output Mode ................................................................................... 79
Pulse Width Modulator Mode.............................................................................. 79
PCA Watchdog Timer ......................................................................................... 80
PCA Registers .................................................................................................... 81