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IBM EM78P312N manual Residue-Voltage Protection, Bit Microcontroller, EM78P809N, Reset

Models: EM78P312N

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EM78P312N

8-Bit Microcontroller

Vdd
/RESET		R
/RESET		D
		D
EM78P312N809N
	Rin	C
		C

Fig. 5-34 External Power-Up Reset Circuit

5.18.2 Residue-Voltage Protection

When battery is replaced, device power (VDD) is taken off but residue-voltage remains. The residue-voltage may trip below VDD minimum, but not to zero. This condition may cause a poor power-on reset. Fig.35 and Fig. 36 show how to build the residue-voltage protection circuit.

Vdd	Vdd
Vdd
EM78P312N	33K
EM78P809N
Q1	10K
/RESET
40K	1N4684

Fig. 5-35 Residue Voltage Protection Circuit 1

Vdd		Vdd
Vdd
EM78P312N		R1
EM78P312N
EM78P809N	Q1
	Q1
/RESET		R2
	40K	R2

Fig. 5-36 Residue Voltage Protection Circuit 2

Product Specification (V1.0) 10.03.2006

• 55

(This specification is subject to change without further notice)

Page 59

Image 59

IBM EM78P312N manual Residue-Voltage Protection, Bit Microcontroller, EM78P809N, Reset

Contents

ELAN MICROELECTRONICS CORP Green Product SpecificationEM78P312N 8-BIT MicrocontrollerAll Rights Reserved ELAN MICROELECTRONICS CORPORATIONCopyright 2006 by ELAN Microelectronics Corporation Pin Assignment ContentsFeatures General DescriptionAPPENDIX Specification Revision HistoryEM78P312N 2 Features1 General Description Pin Assignment8-Bit Microcontroller Pin DescriptionSymbol EM78P312NThis specification is subject to change without further notice 5.1 Functional Block Diagram5 Function Description Fig. 5-1 Functional Block Diagram8-Bit Microcontroller 5.2 Operating RegistersThis specification is subject to change without further notice EM78P312NR2 Program Counter & Stack EM78P312N8-Bit Microcontroller R0 Indirect Addressing Register R1 Time Clock /CounterR3 Status Register EM78P312N8-Bit Microcontroller User Memory SpaceR5 System Control Register EM78P312N8-Bit Microcontroller Bit 0 C Carry flag R4 RAM Select Register8-Bit Microcontroller R6 Port 6 I/O Data Register RB Timer/Counter 4 Control RegisterBit 7 ~ Bit 6 TC4FF1 ~ TC4FF0 Timer/Counter 4 flip-flop control EM78P312N8-Bit Microcontroller Bit 4 ~ Bit 2 TC4CK2 ~ TC4CK 0 Timer/Counter 4 Clock Source SelectRC Timer 4 Data Buffer EM78P312NRFInterrupt Status Flag Register EM78P312N8-Bit Microcontroller RE Interrupt Status Flag Register Bank 1 R7 TC3DB Timer 3 Data Buffer B Bank 1 R5 TC3CR Timer/Counter 3 Control RegisterBit 5 ~ Bit 4 TC3CK1 ~ TC3CK0 Timer/Counter 3 Clock Source Select TC3M = “1” Capture mode Bank 1 R6 TC3DA Timer 3 Data Buffer ATC2M Timer/Counter 2 mode select Bit 2 ~ Bit 0 TC2CK2 ~ TC2CK0 Timer/Counter 2 Clock Source SelectBank 1 R9 TC2DH Timer 2 Data Buffer High Byte Bank 1 RA TC2DL Timer 2 Data Buffer Low Byte8-Bit Microcontroller ADP = “0” Power on ADP = “1” Power downBit 7 ~ Bit 0 ADE7 ~ ADE0 AD input pin enable control EM78P312NEM78P312N TEN = “0” Disable TEN = “1” EnableTBTEN = “0” Disable TBTEN = “1” Enable Bit 2 ~ Bit 0 TBTCK2 ~ TBTCK0 Time Base Timer Clock Source SelectBit 4 ~ Bit 2 BRATE2 ~ BRATE1 Transmit Baud Rate Select TXE = “0” Disable TXE = “1” EnableEM78P312N 8-Bit Microcontroller8-Bit Microcontroller PRE = “0” Disable PRE = “1” Enable Bit 4 PRERR Parity error flagBit 0 RXE Enable receiving RXE = “0” Disable RXE = “1” Enable EM78P312NEDS = “0” Rising edge EDS = “1” Falling edge EM78P312N8-Bit Microcontroller Bit 5 ~ Bit 3 BRS0 ~ BRS2 SPI Clock Source SelectBank EM78P312N8-Bit Microcontroller Bit 2 ~ Bit 1 SPIM1 ~ SPIM0 SPI Transfer Mode SelectWDTE = “0” Disable WDTE = “1” Enable 5.3 Special Purpose RegistersPHE7x = “0” Enable P7x pull high PHE7x = “1” Disable P7x pull highIOC6 ~ IOC9 − I/O Port Control Register Bit 6 INT0EN INT0 enable control INT0EN = “0” General I/OEM78P312N 8-Bit Microcontroller Bit 2 PSR2 ~ Bit 0 PSR0 TCC prescaler bitsBit 5 ~ Bit 3 VOF2 ~ VOF0 Offset voltage bits EM78P312N8-Bit Microcontroller ADOSCR − AD Offset Control Register Address 0ChIMR2 − Interrupt Mask Register 2 Address 0Fh Bit 1 SPIE SPI Interrupt enable bitEM78P312N 8-Bit Microcontroller8-Bit Microcontroller 5.4 CPU Operation ModeEM78P312N Table 4. Wake-up Methods 5.5 AD ConverterEM78P312N 8-Bit MicrocontrollerA/D Sampling Time EM78P312N8-Bit Microcontroller ADC Data RegisterEM78P312N 5.6 Time Base Timer and Keytone GeneratorFig. 5-6 Tone Output Pin Configuration Fig. 5-7 Tone Output Pin Timing Chart8-Bit Microcontroller Fig. 5-8 TBT ConfigurationFig. 5-9 Time Base Timer Timing Chart EM78P312N8-Bit Microcontroller 5.7 UART Universal Asynchronous Receiver/TransmitterFig. 5-10 Function Block Diagram EM78P312N8-Bit Microcontroller 5.7.1 UART Mode5.7.2 Transmitting EM78P312N8-Bit Microcontroller 5.7.3 Receiving5.7.4 Baud Rate Generator EM78P312NEM78P312N 5.8 SPI Serial Peripheral InterfaceFig. 5-13 SPI Block Diagram This specification is subject to change without further noticeEM78P312N 5.8.2 Shift Direction and Sample Phase5.8.1 Serial Clock 5.8.3 Transfer Modec 8-bit Transmit/Receive Mode EM78P312N8-Bit Microcontroller b 8-bit Receive Mode SCK pin EM78P312N8-Bit Microcontroller d Multiple Device Connect /SSEM78P312N 5.9 Timer/CounterRegisters for Timer/Counter 2 Circuit Fig. 5-18 Configuration of Timer/CounterEM78P312N 5.9.1 Timer Mode5.9.2 Counter Mode 5.9.3 Window ModeEM78P312N 5.10 Timer/CounterRegisters for Timer/Counter 3 Circuit Fig. 5-21 Window Mode Timing ChartEM78P312N 5.10.1 Timer Mode5.10.2 Counter Mode 5.10.3 Capture Mode8-Bit Microcontroller 5.11 Timer/CounterEM78P312N EM78P312N 5.11.1 Timer Mode5.11.2 Counter Mode 5.11.3 PDO Mode8-Bit Microcontroller 5.12 TCC/WDT & Prescaler5.11.4 PWM Mode EM78P312NEM78P312N 5.14 Reset and Wake-up5.14.1 Reset 5.13 I/O Ports8-Bit Microcontroller 5.14.2 Wake-up from Sleep Mode5.14.3 Wake-up from Idle Mode EM78P312N8-Bit Microcontroller Reset TypeThis specification is subject to change without further notice EM78P312N8-Bit Microcontroller Register Bank Reset TypeThis specification is subject to change without further notice EM78P312N8-Bit Microcontroller Register Bank Reset TypeThis specification is subject to change without further notice EM78P312NEM78P312N Reset TypeReset Type This specification is subject to change without further notice8-Bit Microcontroller General Purpose Registers 5.14.4 The Status of RST, T, and P of the Status RegisterEM78P312N 8-Bit Microcontroller 5.15 InterruptEM78P312N EM78P312N 5.16 Oscillator5.16.1 Oscillator Modes 5.16.2 Crystal Oscillator/Ceramic Resonators CrystalXTAL EM78P312N8-Bit Microcontroller OSCICrystal/Resonator-Parallel Mode Circuit 5.16.3 External RC Oscillator ModeEM78P312N 8-Bit MicrocontrollerEM78P312N 5.17 Code Option Register5.17.1 Code Option Register Word ENWDTB = “0” Enable ENWDTB = “1” DisableHLP = “0” Low power HLP = “1” High power 5.18 Power-on Considerations5.18.1 External Power-on Reset Circuit 5.17.2 Customer ID Register8-Bit Microcontroller 5.18.2 Residue-Voltage ProtectionRESET EM78P312N8-Bit Microcontroller 5.19 Instruction SetEM78P312N 8-Bit Microcontroller EM78P312NEM78P312N 6 Absolute Maximum Ratings6.1 Absolute Maximum Ratings 6.2 Recommended Operating Conditions8-Bit Microcontroller 7 Electrical Characteristics7.1 DC Electrical Characteristics EM78P312NTa= 25 C, VDD= 3.0V ± 5%, VSS= EM78P312N8-Bit Microcontroller 8-Bit Microcontroller EM78P312NTa=- 40C ~ 85 C, VDD=5V ± 5%, VSS=0V 7.2 AC Electrical CharacteristicEM78P312N 8-Bit MicrocontrollerEM78P312N 7.3 Timing DiagramRESET Timing CLK=0 This specification is subject to change without further noticeOTP MCU APPENDIX A Package TypesEM78P312N 8-Bit Microcontroller

5.18.2 Residue-Voltage Protection

EM78P312N

EM78P809N

/RESET