IBM EM78P447N manual PR2~PR0 are protect bits, protect type as following, Protect

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EM78P447N

8-Bit Microcontroller with OTP ROM

Bit 8 (CLKS): Instruction period option bit.

0:two oscillator periods.

1:four oscillator periods.

Refer to the section on Instruction Set.

Bit 7(ENWDTB): Watchdog timer enable bit.

0:Enable

1:Disable

Bit 6: Type selection for EM78P447NA or EM78P447NB

0:EM78P447NB

1:EM78P447NA

Bit 5 (HLF): XTAL frequency selection

0:XTAL2 type (low frequency, 32.768KHz)

1:XTAL1 type (high frequency)

This bit will affect system oscillation only when Bit4 (OSC) is “1”. When OSC is”0”, HLF must be “0”.

NOTE

The transient point of system frequency between HXT and LXY is around 400 KHz.

Bit 4 (OSC): Oscillator type selection.

0:RC type

1:XTAL type (XTAL1 and XTAL2) Bit 3 (HLP): Power selection.

0:Low power

1:High power

Bit 2~0 (PR2~PR0): Protect Bit

PR2~PR0 are protect bits, protect type as following

	PR2			PR1		PR0		Protect
	0			0		0		Enable
	0			0		1		Enable
	0			1		0		Enable
	0			1		1		Enable
	1			0		0		Enable
	1			0		1		Enable
	1			1		0		Enable
	1			1		1		Disable

Product Specification (V1.1) 03.30.2005								• 27

(This specification is subject to change without further notice)

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Contents EM78P447N Elan Microelectronics Corporation Contents Specification Revision History General Description EM78P447NBWM PIN Assignment EM78P447NAP and EM78P447NAM Pin Description Symbol Pin No Type FunctionEM78P447NAS Pin Description EM78P447NBP and EM78P447NBWM Pin Description Power supplyEM78P447NCK and EN78P447NCM Pin Description EM78P447NDK and EM78P447NDM Pin Description Function Description3 R2 Program Counter & Stack Operational Registers1 R0 Indirect Addressing Register 2 R1 Time Clock /CounterFffh Call RET Retl RetiData Memory Configuration R5, R6 and R7 are I/O registers 5 R4 RAM Select Register6 R5~R7 Port 5 ~ Port7 7 R8~R1F and R20~R3E General Purpose RegisterControl Register Special Purpose Registers8 R3F Interrupt Status Register AccumulatorWDT Rate 3 IOC5 ~ IOC7 I/O Port Control RegisterIocb Wake-up Control Register for Port6 TCC RateWUE Ioce WDT Control RegisterExie Iocf Interrupt Mask RegisterTCC/WDT & Prescaler TCC and WDT Block DiagramIOD I/O PortsReset Reset and Wake-upSLEEP2 SLEEP1 Usage of Sleep1 and Sleep2 ModeSummary of the Initialized Values for Registers Address Name Reset Type BitIocb R3FISRExif Tcif WUE7 WUE6 WUE5 WUE4Events that may Affect the T and P Status Previous status before resetPrevious value before reset Status of RST, T, and P of Status RegisterInterrupt Controller Reset Block DiagramOscillator Modes OscillatorMode Fxt max.MHz Crystal Oscillator/Ceramic ResonatorsXTALSummary of Maximum Operating Speeds ConditionsLXT External RC Oscillator ModeOscillator Type Frequency Mode C1pF C2pF HXTCode Option Register Word Code Option RegisterProtect PR2~PR0 are protect bits, protect type as followingBit 12~0 Customer’s ID code Power On ConsiderationsExternal Power On Reset Circuit Customer ID Register WordResidue-Voltage Protection ResetInstruction Set Slep NOPDAA ContwRRC R Djza RDJZ R Rrca RAC Test Input/Output W aveform Timing DiagramItems Rating DC Electrical CharacteristicSymbol Parameter Condition Min Typ Max Unit Ta= 25 C, VDD= 5.0V±5%, VSS=Symbol Parameter Conditions Min Typ Max Unit AC Electrical CharacteristicTa=- -40 C ~ 85 C, VDD=5V ±5%, VSS=0V Vih, Vil of TCC, /INT, /RESET Pin Device characteristicPort5, Port6 Port7 Voh vs. Ioh,VDD=5V Port5, Port6, and Port7 Voh vs. Ioh, VDD=3V Vol/Iol VDD=5V Vol/Iol VDD=3V Vol/Iol 100 Vol/Iol WDT Cext=100pF, Typical RC OSC Frequency Typical ICC1 and ICC2 vs. Temperature Maximum ICC1 and ICC2 vs. Temperature Typical ISB1 and ISB2 vs. Temperature Maximum ISB1 and ISB2 vs. Temperature EM78P447N HXT ImA Package Type Pin Count Package Size Lead plastic dual inline package（DIP）－ 300 milLead plastic dual inline package（DIP）－ 600 mil Lead plastic dual inline skinny package（DIP）－ 300 mil838 27TYP EM78P447N