IBM EM78P809N EM78P809N, 4.18.2 Residue-Voltage Protection

EM78P809N

8-Bit Microcontroller

60 • Product Specification (V1.0) 07.26.2005

(This specification is subject to change without further notice)

current leakage from the /RESET pi n is about ±5μA, it is recommended that R should

not be greater than 40K. In this way, the / RESET pin voltage is held below 0.2V. The

diode (D) acts as a short circuit at the mo ment of power down. The capacitor C will

discharge rapidly and fully. Rin, the cur rent-limited resistor, will prevent high curr ent or

ESD (electrostatic discharge) from flowing to pin /R ESET.

EM78P809N

/RESET

Vdd

D

R

Rin C

Fig. 35. External Power-Up Reset Circuit

4.18.2 Residue-Voltage Protection

When battery is replaced, device pow er (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 F ig.36 show how to build the residue-volta ge

protection circuit.

EM78P809N

/RESET

Vdd

40K

Q1

1N4684

10K

33K

Vdd

Fig. 36. Residue Voltage Protection Circuit 1

Contents

Main EM78P809N 8-BIT Microcontroller Product Specification DOC. VERSION 1.0 ELAN MCCROELECTRONICS CORP. All Rights Reserved Printed in Taiwan ELAN MICROELECTRONICS CORPORATION Contents Page 1 General Description 2 Features 2.1 CPU 2.2 Applications EM78P809N 8-Bit Microcontroller 3 Pin Assignment Fig. 1. Pin Assignment 4 Pin Description Table 1 Symbol Pin No. Type Function EM78P809N 8-Bit Microcontroller Symbol Pin No. Type Function 4 Function Description 4.1 Functional Block Diagram 8-Bit Microcontroller Fig. 3. Operating Registers 4.2 Operating Registers 05 06 07 08 09 0A 0B 0C 0D 0E 0F 01 10 : 1F 20 : 3F Page 8-Bit Microcontroller User Memory Space On-chip Program Memory A11 A10 A9 A8 A7 ~ A0 8 Product Specification (V1.0) 07.26.2005 Page Page Page Page Page Page Page Page Page Page Page Page Page Page 4.3 Special Purpose Registers Page Page Page 4.4 CPU Operation Mode Page 8-Bit Microcontroller * Dont care ** Interrupt request flag will be recorded 4.5 AD Converter Registers for AD Converter Circuit * R_BANK : Register Bank (bits 7, 6 of R3), R/W: Read / Write * SPR : Special Purpose Register s Page 8-Bit Microcontroller Table 5 4.6 Time Base Timer and Keytone Generator Registers for AD Converter Circuit D Q TBKTC MUX MUX 8-Bit Microcontroller Product Specification (V1.0) 07.26 .2 005 33 4.7 UART (Universal Asynchronous Receiver/Transmitter) Registers for UART Circuit R_BANK Address NAME Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Fig. 11. Function Block Diagram EM78P809N 4.7.1 UART MODE: Mode 3 Mode 1 Mode 2 EM78P809N 4.7.2 Transmitting: 4.7.3 Receiving: EM78P809N 8-Bit Microcontroller 4.8 SPI (Serial Peripheral Interface) Registers for the SPI Circuit R_BANK Address NAME Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Fig. 14. SPI Block Diagram EM78P809N 4.8.1 Serial Clock: SPID 4.8.2 Shift Direction and Sample Phase: 4.8.3 Transfer Mode: /SCK pin RBF WBE SPIF SPID SI p i n 8-Bit Microcontroller SPIS RBF WBE SPIF SPID shift start shift start SO pi n 4.9 Timer/Counter 2 Registers for Timer/Counter 2 Cir cuit R_BANK Address NAME Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 EM78P809N 4.9.1 Timer Mode: 4.9.2 Counter Mode: 4.10 Timer/Counter 3 EM78P809N 4.10.1 Timer Mode: 4.10.2 Counter Mode: 4.10.3 Capture mode: 4.11 Timer/Counter 4 EM78P809N 4.11.1 Timer Mode 4.11.2 Counter Mode 4.11.3 PDO Mode Source Clock Up-counter TCR4 TC4 Interrupt 4.12 TCC/WDT & Prescaler EM78P809N 4.13 I/O Ports 4.14 RESET and Wake-up 4.14.1 RESET EM78P809N 4.14.2 Wake-up from SLEEP Mode: 4.14.3 Wake-up from IDLE mode: 8-Bit Microcontroller Product Specification (V1.0) 07.26 .2 005 49 Table 6. Summary of the Initialized Values for Registers Address Name Reset Type Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 8-Bit Microcontroller 50 Product Specification (V1.0) 07.26.2005 Register Bank 0 Address Name Reset Type Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 8-Bit Microcontroller Product Specification (V1.0) 07.26 .2 005 51 Register Bank 1 Address Name Reset Type Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 8-Bit Microcontroller 52 Product Specification (V1.0) 07.26.2005 Register Bank 2 Address Name Reset Type Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bi t 0 EM78P809N 4.14.4 The Status of RST, T, and P of STATUS Register 4.15 Interrupt EM78P809N 4.16 Oscillator 4.16.1 Oscillat or Modes 4.16.2 Crystal Oscil lator/Ceramic Resonators (Crystal) Page EM78P809N 4.16.3 External RC Oscillator Mode EM78P809N 4.17 Code Option Register 4.17.1 Code Option Register (Word 0) EM78P809N 4.17.2 Customer ID Register 4.18 Power-on Considerations 4.18.1 External Power-on Reset Circuit EM78P809N 4.18.2 Residue-Voltage Protection 4.19 Instruction Set Page 8-Bit Microcontroller Note1: This instructi on is applicable to IOC6 ~ IOCA, IMR1, IMR2 onl y. 5 Absolute Maximum Ratings 5.1 Absolute Maximum Ratings 5.2 Recommended Operating Conditions ( Vss = 0V ) 8-Bit Microcontroller 6 Electrical Characteristics 6.1 DC Electrical Characteristics (Ta= 25 C, VDD= 5.0 V 5%, VSS= 0V) Symbol Parameter Condition Min. Typ. Max. Unit *The typical value is based on characterization results at 25C 8-Bit Microcontroller Product Specification (V1.0) 07.26 .2 005 65 (Ta= 25 C, VDD= 3.0 V 5%, VSS= 0V) Symbol Parameter Condition Min. Typ. Max. Unit 8-Bit Microcontroller 66 Product Specification (V1.0) 07.26.2005 A/D Converter Characteristic (VDD =2.5V to 5.5V, Vss=0V, Ta = -40 to 85) Symbol Parameter Condi tion Min. Typ. Max. Unit 6.2 AC Electrical Characteristic * N= selected prescaler ratio (Ta=- 40C ~ 85 C, VDD=5V 5%, VSS=0V) 68 Product Specification (V1.0) 07.26.2005 6.3 Timing Diagram RESET Timing (CLK="0") TCC Input Timing (CLKS="0") AC Test Input/Output Waveform APPENDIX Package Types: