Oscillator Modes | IBM EM78P447N specification

EM78P447N

8-Bit Microcontroller with OTP ROM

	VCC
	D	P	Q
/IRQn	D	R	Q
/IRQn	CLK		_
		C	Q
	RF	L
	RF

/RESET

IRQn

INT

RFRD IRQm

ENI/DISI

		Q	P	D				IOD
			R
			R
		_	C CLK
		_	C CLK			IOCFWR
IOCF		Q	L

IOCFRD

RFWR

Fig. 9 Interrupt Input Circuit

4.7 Oscillator

4.7.1 Oscillator Modes

The EM78P447N can operate in three different oscillator modes, i.e., high XTAL (HXT) oscillator mode, low XTAL (LXT) oscillator mode, and External RC oscillator mode (ERC) oscillator mode. User can select one of them by programming MS, HLF and HLP in the Code Option Register. Table 10 depicts how these three modes are defined.

The maximum limit for operational frequencies of crystal/resonator under different VDDs is listed in Table 10.

Table 10 Oscillator Modes Defined by MS and HLP

Mode		MS
ERC(External RC oscillator mode)		0
HXT(High XTAL oscillator mode)		1
LXT(Low XTAL oscillator mode)		1

HLF

*X

1

0

HLP

*X

*X

0

NOTE

1.X, Don’t care

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

Product Specification (V1.1) 03.30.2005

• 23

(This specification is subject to change without further notice)

Image 27

IBM EM78P447N manual Oscillator Modes

Contents

EM78P447N Elan Microelectronics Corporation Contents Specification Revision History General Description EM78P447NBWM PIN Assignment Symbol Pin No Type Function EM78P447NAP and EM78P447NAM Pin DescriptionEM78P447NAS Pin Description Power supply EM78P447NBP and EM78P447NBWM Pin DescriptionEM78P447NCK and EN78P447NCM Pin Description EM78P447NDK and EM78P447NDM Pin Description Function Description 3 R2 Program Counter & Stack Operational Registers1 R0 Indirect Addressing Register 2 R1 Time Clock /Counter Fffh Call RET Retl Reti Data 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 Register Control Register Special Purpose Registers8 R3F Interrupt Status Register Accumulator WDT Rate 3 IOC5 ~ IOC7 I/O Port Control RegisterIocb Wake-up Control Register for Port6 TCC Rate WUE Ioce WDT Control Register Exie Iocf Interrupt Mask Register TCC/WDT & Prescaler TCC and WDT Block Diagram IOD I/O Ports Reset Reset and Wake-up SLEEP2 SLEEP1 Usage of Sleep1 and Sleep2 Mode Summary of the Initialized Values for Registers Address Name Reset Type Bit Iocb R3FISRExif Tcif WUE7 WUE6 WUE5 WUE4 Events that may Affect the T and P Status Previous status before resetPrevious value before reset Status of RST, T, and P of Status Register Interrupt Controller Reset Block Diagram Oscillator Oscillator ModesMode Fxt max.MHz Crystal Oscillator/Ceramic ResonatorsXTALSummary of Maximum Operating Speeds Conditions LXT External RC Oscillator ModeOscillator Type Frequency Mode C1pF C2pF HXT Code Option Register Word Code Option Register Protect PR2~PR0 are protect bits, protect type as following Bit 12~0 Customer’s ID code Power On ConsiderationsExternal Power On Reset Circuit Customer ID Register Word Residue-Voltage Protection Reset Instruction Set Slep NOPDAA Contw RRC R Djza RDJZ R Rrca R AC Test Input/Output W aveform Timing Diagram Items Rating DC Electrical CharacteristicSymbol Parameter Condition Min Typ Max Unit Ta= 25 C, VDD= 5.0V±5%, VSS= AC Electrical Characteristic Symbol Parameter Conditions Min Typ Max UnitTa=- -40 C ~ 85 C, VDD=5V ±5%, VSS=0V Vih, Vil of TCC, /INT, /RESET Pin Device characteristic Port5, 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 mil Lead plastic dual inline package（DIP）－ 600 mil Lead plastic dual inline skinny package（DIP）－ 300 mil 838 27TYP EM78P447N