ELANsat Tech EM78P156N OTP ROM, EM78P156N, 4.6 Interrupt

EM78P156N

OTP ROM

4.6 Interrupt

The EM78P156N has three falling-edge interrupts listed below:

(1)TCC overflow interrupt

(2)Port 6 Input Status Change Interrupt

(3)External interrupt [(P60, /INT) pin].

Before the Port 6 Input Status Change Interrupt is enabled, reading Port 6 (e.g. "MOV R6,R6") is necessary. Each pin of Port 6 will have this feature if its status changed. Any pin configured as output or P60 pin configured as /INT is excluded from this function. The Port 6 Input Status Changed Interrupt can wake up the EM78P156N from the sleep mode if Port 6 is enabled prior to going into the sleep mode by executing SLEP. When the chip wakes-up, the controller will continue to execute the succeeding address if the global interrupt is disabled or branch to the interrupt vector 008H if the global interrupt is enabled.

RF is the interrupt status register that records the interrupt requests in the relative flags/bits. IOCF is an 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 008H. Once in the interrupt service routine, the source of an interrupt can be determined by polling the flag bits in RF. 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 (RF) is set regardless of the status of its mask bit or the execution of ENI. Note that the outcome of RF will be the logic AND of RF and IOCF (refer to Fig. 10). 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 001H.

This specification is subject to change without prior notice. 25

07.29.2004 (V1.2)

Contents

8-BIT MICRO-CONTROLLER Version EM78P156N Specification Revision History Version Content Application Note 1. GENERAL DESCRIPTION 2. FEATURES Page 3. PIN ASSIGNMENTS Table 2 EM78P156NAS Pin Description Table 3 EM78P156NKM Pin Description 4. FUNCTION DESCRIPTION 3.R2 (Program Counter) & Stack On-chipProgram Memory Fig. 3 Program Counter Organization Address R PAGE registers IOC PAGE registers CONT IOC5 4. R3 (Status Register) Bit 0 (C) • Bit (DC) (Z) 4.2 Special Purpose Registers 1. A (Accumulator) 2. CONT (Control Register) Bit 3 (PAB) Bit 4 (TE) 3. IOC5 ~ IOC6 (I/O Port Control Register) 4. IOCA (Prescaler Counter Register) 5. IOCB (Pull-downControl Register) Bit 0 (/PD0) Bit 1 (/PD1) Bit 5 (OD5) Bit 6 (OD6) Bit 7 (OD7) 7. IOCD (Pull-highControl Register) Bit 0 (/PH0) 4.3 TCC/WDT & Prescaler 4.4 I/O Ports Fig. 6 The Circuit of I/O Port and I/O Control Register for Port Fig. 7(a) The Circuit of I/O Port and I/O Control Register for P60 (/INT) Fig. 7(b) The Circuit of I/O Port and I/O Control Register for P61~P67 Fig. 7(c) Block Diagram of I/O Port 6 with Input Change Interrupt/Wake-up Table 4 Usage of Port 6 Input Change Wake-up/InterruptFunction (I) (II) Fig. 8 The Circuit of I/O Port with R-option(P50,P51) 4.5RESET and Wake-up 1.RESET Page Table 5 The Summary of the Initialized Values for Registers 2.The Status of RST, T, and P of STATUS Register Table 6 The Values of RST, T and P after RESET Fig. 9 Block Diagram of Controller Reset 4.6 Interrupt 4.7Oscillator 1.Oscillator Modes Table 8 Oscillator Modes Defined by OSC and HLP Table 9 The Summary of Maximum Operating Speeds 2. Crystal Oscillator/Ceramic Resonators (XTAL) Fig. 11 Circuit for External Clock Input Fig. 12 Circuit for Crystal/Resonator Table 10 Capacitor Selection Guide for Crystal Oscillator or Ceramic Resonator 3. External RC Oscillator Mode 4.8CODE Option Register 1. Code Option Register (Word 0) •Bit 12 、11 、10 、9:Not used. Reserved Bit 8 (CLKS) Bit 7(ENWDTB) Bit 6: 4.9Power On Considerations 4.10 External Power On Reset Circuit 4.11 Residue-VoltageProtection Fig. 15 Circuit 1 for the Residue Voltage Protection 4.12 Instruction Set Page Page 4.13 Timing Diagrams AC Test Input/Output Waveform RESET Timing (CLK="0") TCC Input Timing (CLKS="0") 5.ABSOLUTE MAXIMUNM RATINGS EM78P156N 6.ELECTRICAL CHARACTERISTICS 6.2 AC Electrical Characteristic Vih/Vil (Input pins with schmitt inverter) Vth (Input thershold voltage) of I/O pins Voh/Ioh (5V) Vol/Iol (5V) Fig. 21 Port5, Port6 Vol vs. Iol, VDD Vol/Iol (3V) Fig. 22 Port5, Port6 Vol vs. Iol, VDD WDT Time out Cext = 100pF, Typical RC Frequency vs. VDD Typical ICC1 and ICC2 vs. Temperature Maximum ICC1 and ICC2 vs. Temperature Typical ICC3 and ICC4 vs. Temperature Maximum ICC3 and ICC4 vs. Temperature Typical ISB1 and ISB2 vs. Temperature Maximum ISB1 and ISB2 vs. Temperature Page EM78P156N-JHXT EM78P156N-JLXT EM78P156N-GHXT EM78P156N-GLXT APPENDIX Package Information 18-LeadPlastic Small Outline (SOP) — 300 mil 20-LeadPlastic Small Outline (SSOP) — 209 mil Quality Assurance And Reliability Address Trap Detect