IBM EM78P447N manual Interrupt, Controller Reset Block Diagram

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EM78P447N

8-Bit Microcontroller with OTP ROM

	VDD
Oscillator	D	Q	CLK
	CLK		CLK
	CLK
	CLR

Power-on

Reset

Voltage

Detector

WDTE

WDT	WDT Timeout	Setup Time	RESET

/RESET

Fig. 8 Controller Reset Block Diagram

4.6 Interrupt

The EM78P447N has two interrupts listed below:

(1)TCC overflow interrupt

(2)External interrupt (/INT pin).

R3F is the interrupt status register that records the interrupt requests in the relative flags/bits. IOCF is the interrupt mask register. The global interrupt is enabled by the ENI instruction and is disabled by the DISI instruction. When one of the interrupts (enabled) occurs, the next instruction will be fetched from address 001H. Once in the interrupt service routine, the source of an interrupt can be determined by polling the flag bits in R3F. The interrupt flag bit must be cleared by instructions before leaving the interrupt service routine and before interrupts are enabled to avoid recursive interrupts.

The flag (except ICIF bit) in the Interrupt Status Register (R3F) is set regardless of the status of its mask bit or the execution of ENI. Note that the outcome of R3F are the logic AND of R3F and IOCF (refer to Fig. 9). The RETI instruction ends the interrupt routine and enables the global interrupt (the execution of ENI).

When an interrupt is generated by the INT instruction (enabled), the next instruction will be fetched from address 002H.

22 •	Product Specification (V1.1) 03.30.2005

(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 EM78P447NAS Pin Description Symbol Pin No Type FunctionEM78P447NAP and EM78P447NAM Pin Description EM78P447NCK and EN78P447NCM Pin Description Power supplyEM78P447NBP and EM78P447NBWM Pin Description Function Description EM78P447NDK and EM78P447NDM Pin Description2 R1 Time Clock /Counter Operational Registers1 R0 Indirect Addressing Register 3 R2 Program Counter & StackCall RET Retl Reti FffhData Memory Configuration 7 R8~R1F and R20~R3E General Purpose Register 5 R4 RAM Select Register6 R5~R7 Port 5 ~ Port7 R5, R6 and R7 are I/O registersAccumulator Special Purpose Registers8 R3F Interrupt Status Register Control RegisterTCC Rate 3 IOC5 ~ IOC7 I/O Port Control RegisterIocb Wake-up Control Register for Port6 WDT RateIoce WDT Control Register WUEIocf Interrupt Mask Register ExieTCC and WDT Block Diagram TCC/WDT & PrescalerI/O Ports IODReset and Wake-up ResetUsage of Sleep1 and Sleep2 Mode SLEEP2 SLEEP1Address Name Reset Type Bit Summary of the Initialized Values for RegistersWUE7 WUE6 WUE5 WUE4 R3FISRExif Tcif IocbStatus of RST, T, and P of Status Register Previous status before resetPrevious value before reset Events that may Affect the T and P StatusController Reset Block Diagram InterruptMode OscillatorOscillator Modes Conditions Crystal Oscillator/Ceramic ResonatorsXTALSummary of Maximum Operating Speeds Fxt max.MHzHXT External RC Oscillator ModeOscillator Type Frequency Mode C1pF C2pF LXTCode Option Register Code Option Register WordPR2~PR0 are protect bits, protect type as following ProtectCustomer ID Register Word Power On ConsiderationsExternal Power On Reset Circuit Bit 12~0 Customer’s ID codeReset Residue-Voltage ProtectionInstruction Set Contw NOPDAA SlepRrca R Djza RDJZ R RRC RTiming Diagram AC Test Input/Output W aveformTa= 25 C, VDD= 5.0V±5%, VSS= DC Electrical CharacteristicSymbol Parameter Condition Min Typ Max Unit Items RatingTa=- -40 C ~ 85 C, VDD=5V ±5%, VSS=0V AC Electrical CharacteristicSymbol Parameter Conditions Min Typ Max Unit Device characteristic Vih, Vil of TCC, /INT, /RESET PinPort5, 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 Lead plastic dual inline package（DIP）－ 300 mil Package Type Pin Count Package SizeLead plastic dual inline skinny package（DIP）－ 300 mil Lead plastic dual inline package（DIP）－ 600 mil838 27TYP EM78P447N