Samsung C8249, P8245, P8249, S3C8245 IRET

INSTRUCTION SET S3C8245/P8245/C8249/P8249

6-46

IRET — Interrupt Return

IRET IRET (Normal) IRET (Fast)

Operation: FLAGS ← @SP PC ↔ IP

SP ← SP + 1 FLAGS ← FLAGS'

PC ← @SP FIS ← 0

SP ← SP + 2

SYM(0) ← 1

This instruction is used at the end of an interrupt service routine. It restores the flag register and the

program counter. It also re-enables global interrupts. A "normal IRET" is executed only if the fast

interrupt status bit (FIS, bit one of the FLAGS register, 0D5H) is cleared (= "0"). If a fast interrupt

occurred, IRET clears the FIS bit that was set at the beginning of the service routine.

Flags: All flags are restored to their original settings (that is, the settings before the interrupt occurred).

Format:

IRET

(Normal) Bytes Cycles Opcode (Hex)

opc 110 (internal stack) BF

12 (internal stack)

IRET

(Fast) Bytes Cycles Opcode (Hex)

opc 1 6 BF

Example: In the figure below, the instruction pointer is initially loaded with 100H in the main program before

interrupts are enabled. When an interrupt occurs, the program counter and instruction pointer are

swapped. This causes the PC to jump to address 100H and the IP to keep the return address. The

last instruction in the service routine normally is a jump to IRET at address FFH. This causes the

instruction pointer to be loaded with 100H "again" and the program counter to jump back to the

main program. Now, the next interrupt can occur and the IP is still correct at 100H.

IRET

Interrupt

Service

Routine

JP to FFH

0H

FFH

100H

FFFFH

NOTE: In the fast interrupt example above, if the last instruction is not a jump to IRET, you must pay

attention to the order of the last two instructions. The IRET cannot be immediately proceeded by a

clearing of the interrupt status (as with a reset of the IPR register).

Contents

Main NOTIFICATION OF REVISIONS REVISION HISTORY REVISION DESCRIPTIONS 1. DEVICE TYPE 2. FEATURES 3. ELECTRICAL DATA Page Important Notice Preface Page Table of Contents Part I Programming Model Chapter 1 Product Overview Chapter 2 Address Spaces Chapter 3 Addressing Modes Chapter 4 Control Registers Chapter 5 Interrupt Structure Chapter 6 Instruction Set Part II Hardware Descriptions Chapter 7 Clock Circuit Chapter 8 nRESET and Power-Down Chapter 9 I/O Ports Chapter 10 Basic Timer Chapter 11 8-bit Timer A/B Chapter 12 16-bit Timer 0/1 Chapter 13 Watch Timer Chapter 14 LCD Controller/Driver Page Table of Contents Page Page Page List of Figures List of Tables List of Tables List of Programming Tips Page List of Register Descriptions List of Register Descriptions Page Page List of Instruction Descriptions 1 S3C8-SERIES MICROCONTROLLERS S3C8245/P8245/C8249/P8249 MICROCONTROLLER OTP FEATURES S3C8245/P8245/C8249/P8249 PRODUCT OVERVIEW Figure 1-1. Block Diagram 1-3 PRODUCT OVERVIEW S3C8245/P8245/C8249/P8249 1-4 PIN ASSIGNMENT S3C8245/C8249 Figure 1-2. S3C8245/C8249 Pin Assignments (80-QFP-1420C) (80-QFP-1420C) S3C8245/P8245/C8249/P8249 PRODUCT OVERVIEW 1-5 S3C8245/C8249 (80-TQFP-1212) Figure 1-3. S3C8245/C8249 Pin Assignments (80-TQFP-1212) PIN DESCRIPTIONS Page PIN CIRCUITS V Figure 1-7. Pin Circuit Type D-4 (P0) In Figure 1-4. Pin Circuit Type B (nRESET) Figure 1-8. Pin Circuit Type E-2 (P1) Figure 1-9. Pin Circuit Type F-10 (P2.0P2.6) Figure 1-11. Pin Circuit Type H (SEG/COM) Figure 1-10. Pin Circuit Type F-18 (P2.7/VLDREF) Figure 1-12. Pin Circuit Type H-4 Figure 1-13. Pin Circuit Type H-14 (P4, P5) 2 PROGRAM MEMORY (ROM) REGISTER ARCHITECTURE ADDRESS SPACES S3C8245/P8245/C8249/P8249 ~ ~ ~ Figure 2-2. Internal Register File Organization ~ ~ ~ ~ + Page S3C8245/P8245/C8249/P8249 ADDRESS SPACES 2-7 Figure 2-4. Set 1, Set 2, Prime Area Register, and LCD Data Register Map ~ ~ Page + REGISTER ADDRESSING ADDRESS SPACES S3C8245/P8245/C8249/P8249 Figure 2-9. Register File Addressing 2-12 ~ ~ ~~~ + Figure 2-11. 4-Bit Working Register Addressing Figure 2-12. 4-Bit Working Register Addressing Example Page S3C8245/P8245/C8249/P8249 ADDRESS SPACES Figure 2-14. 8-Bit Working Register Addressing Example 2-17 SYSTEM AND USER STACK Page Page 3 REGISTER ADDRESSING MODE (R) Figure 3-2. Working Register Addressing Figure 3-1. Register Addressing INDIRECT REGISTER ADDRESSING MODE (IR) INDIRECT REGISTER ADDRESSING MODE (Continued) Figure 3-4. Indirect Register Addressing to Program Memory ~ ~ ~ ~ Figure 3-5. Indirect Working Register Addressing to Register File INDIRECT REGISTER ADDRESSING MODE (Concluded) Figure 3-6. Indirect Working Register Addressing to Program or Data Memory INDEXED ADDRESSING MODE (X) ~ ~ ~ ~ + INDEXED ADDRESSING MODE (Continued) + Figure 3-8. Indexed Addressing to Program or Data Memory with Short Offset ~ ~ S3C8245/P8245/C8249/P8249 ADDRESSING MODES + 3-9 INDEXED ADDRESSING MODE (Concluded) Figure 3-9. Indexed Addressing to Program or Data Memory ~ ~ DIRECT ADDRESS MODE (DA) DIRECT ADDRESS MODE (Continued) Figure 3-11. Direct Addressing for Call and Jump Instructions INDIRECT ADDRESS MODE (IA) RELATIVE ADDRESS MODE (RA) + IMMEDIATE MODE (IM) 4 Page Page CONTROL REGISTERS S3C8245/P8245/C8249/P8249 4-4 FLAGS - System Flags Register D5H Figure 4-1. Register Description Format Set 1 ADCON A/D Converter Control Register F7H Set 1, Bank 1 BTCON CLKCON EMT FLAGS IMR I NTPND IPH IPL IPR IRQ LCON Page LMOD OSCCON P0CONH Port 0 Control Register (High Byte) E0H Set 1,Bank 0 P0CONL Port 0 Control Register (Low Byte) E1H Set 1, Bank 0 P0INT Port 0 Interrupt Control Register E2H Set 1, Bank 0 P0PND Port 0 Interrupt Pending Register E3H Set 1, Bank 0 Page P1CONH Port 1 Control Register (High Byte) E4HSet 1, Bank 0 P1CONL Port 1 Control Register (Low Byte) E5HSet 1, Bank 0 P1PUP Port 1 Pull-up Control Register F5H Set 1, Bank 0 Page P2CONH Port 2 Control Register (High Byte)E6HSet 1, Bank 0 P2CONL Port 2 Control Register (Low Byte)E7HSet 1, Bank 0 P3CONH Port 3 Control Register (High Byte)E8HSet 1, Bank 0 P3CONL Port 3 Control Register (Low Byte)E9HSet 1, Bank 0 P4CONH Port 4 Control Register (High Byte)ECH Set 1, Bank 1 P4CONL Port 4 Control Register (Low Byte)EDHSet 1, Bank 1 P5CONH P5CONL Port 5 Control Register (Low Byte)EFHSet 1, Bank 1 PP RP0 RP1 SIOCON SPH SPL STPCON SYM T0CON T1CON T A CON T B CON VLDCON WT CON 5 INTERRUPT STRUCTURE S3C8245/P8245/C8249/P8249 5-2 Figure 5-1. S3C8-Series Interrupt Types S3C8245/P8245/C8249/P8249 INTERRUPT STRUCTURE 5-3 Figure 5-2. S3C8245/C8249 Interrupt Structure Page Page Page Page Page Page Page Page INTERRUPT STRUCTURE S3C8245/P8245/C8249/P8249 Figure 5-8. Interrupt Priority Register (IPR) 5-12 Page Page Page Page Page Page 6 Page Page Page Page Page Page Page Page Page Page Page Page ADC ADD Add AND Logical AND BAND Bit AND BCP Bit Compare BITC Bit Complement BITR BITS BOR BTJRF Bit Test, Jump Relative on False BTJRT BXOR CALL CCF CLR COM CP CPIJE CPIJNE Page DA DEC DECW DI DIV DJNZ EI ENTER EXIT IDLE INC INCW IRET JP JR Page LD LDB Page Page LDC/LDE LDCD/LDED LDCI/LDEI LDCPD/LDEPD LDCPI/LDEPI LDW MULT NEXT NOP OR POP POPUD POPUI PUSH PUSHUD PUSHUI RCF RET RL RLC RR RRC SB0 SB1 SBC SCF SRA SRP/SRP0/SRP1 STOP SUB SWAP TCM TM WFI XOR 7 CLOCK CIRCUIT S3C8245/P8245/C8249/P8249 7-2 Figure 7-3. System Clock Circuit Diagram Page CLOCK CIRCUIT S3C8245/P8245/C8249/P8249 7-4 Figure 7-5. Oscillator Control Register (OSCCON) Figure 7-6. STOP Control Register (STPCON) 8 SYSTEM nRESET Page Page Page POWER-DOWN MODES Page 9 Page Page I/O PORTS S3C8245/P8245/C8249/P8249 9-4 Figure 9-1. Port 0 High-Byte Control Register (P0CONH) Figure 9-2. Port 0 Low-Byte Control Register (P0CONL) 9-5 Figure 9-3. Port 0 Interrupt Control Register (P0INT) Figure 9-4. Port 0 Interrupt Pending Register (P0PND) Page 9-7 Figure 9-6. Port 1 Low-Byte Control Register (P1CONL) Figure 9-7. Port 1 Pull-up Control Register (P1PUP) Page Figure 9-9. Port 2 Low-Byte Control Register (P2CONL) 9-9 Page Figure 9-11. Port 3 Low-Byte Control Register (P3CONL) 9-11 Page Figure 9-13. Port 4 Low-Byte Control Register (P4CONL) 9-13 Page Figure 9-15. Port 5 Low-Byte Control Register (P5CONL) 9-15 Page 10 BASIC TIMER S3C8245/P8245/C8249/P8249 Figure 10-1. Basic Timer Control Register (BTCON) 10-2 Page BASIC TIMER S3C8245/P8245/C8249/P8249 Figure 10-2. Basic Timer Block Diagram 10-4 11 8-BIT TIMER A Page Page Figure 11-2. Timer A Functional Block Diagram 8-BIT TIMER B Figure 11-3. Timer B Functional Block Diagram 8-BIT TIMER A/B S3C8245/P8245/C8249/P8249 11-6 Figure 11-4. Timer B Control Register (TBCON) Figure 11-5. Timer B Data Registers (TBDATAH/L) Page Figure 11-6. Timer B Output Flip-Flop Waveforms in Repeat Mode F F PROGRAMMING TIP To generate a one pulse signal through P3.0 12 16-BIT TIMER 0 Page Figure 12-2. Timer 0 Functional Block Diagram 16-BIT TIMER 0/1 S3C8245/P8245/C8249/P8249 12-4 Figure 12-3. Timer 0 Counter Register (T0CNTH/L) Figure 12-4. Timer 0 Data Register (T0DATAH/L) 16-BIT TIMER 1 Page Page 16-BIT TIMER 0/1 S3C8245/P8245/C8249/P8249 Figure 12-6. Timer 1 Functional Block Diagram 12-8 S3C8245/P8245/C8249/P8249 16-BIT TIMER 0/1 12-9 Figure 12-7. Timer 1 Control Register (T1CNTH/L) Figure 12-8. Timer 1 Data Register (T1DATAH/L) Page 13 Page S3C8245/P8245/C8249/P8249 WATCH TIMER 13-3 WATCH TIMER CIRCUIT DIAGRAM Figure 13-1. Watch Timer Circuit Diagram Page 14 LCD CIRCUIT DIAGRAM Figure 14-2. LCD Circuit Diagram Figure 14-3. LCD Display Data RAM Organization Page Page Page Page LCD CONTROLLER/DRIVER S3C8245/P8245/C8249/P8249 14-8 Figure 14-5. Select/No-Select Bias Signals in 1/2 Duty, 1/2 Bias Display Mode Figure 14-6. Select/No-Select Bias Signals in 1/3 Duty, 1/3 Bias Display Mode Figure 14-7. LCD Signal and Wave Forms Example in 1/2 Duty, 1/2 Bias Display Mode Figure 14-8. LCD Signals and Wave Forms Example in 1/3 Duty, 1/3 Bias Display Mode S3C8245/P8245/C8249/P8249 LCD CONTROLLER/DRIVER Figure 14-9. LCD Signals and Wave Forms Example in 1/4 Duty, 1/3 Bias Display Mode 14-11 LCD CONTROLLER/DRIVER S3C8245/P8245/C8249/P8249 14-12 Figure 14-10. Voltage Dividing Resistor Circuit Diagram 15 FUNCTION DESCRIPTION Page Page Figure 15-3. A/D Converter Functional Block Diagram S3C8245/P8245/C8249/P8249 A/D CONVERTER Figure 15-4. Recommended A/D Converter Circuit for Highest Absolute Accuracy 15-5 Page 16 Page S3C8245/P8245/C8249/P8249 SERIAL I/O INTERFACE 16-3 SIO Pre-scaler Register (SIOPS) F2H, Set 1, Bank 0 R/W .7 .6 .5 .4 .3 .2 .1 .0MSB LSB Baud rate = (f Figure 16-3. SIO Functional Block Diagram /4)/(SIOPS + 1) Figure 16-2. SIO Pre-scale Registers (SIOPS) SERIAL I/O INTERFACE S3C8245/P8245/C8249/P8249 16-4 SERIAL I/O TIMING DIAGRAM Figure 16-4. Serial I/O Timing in Transmit/Receive Mode (Tx at falling, SIOCON.4 = 0) Figure 16-5. Serial I/O Timing in Transmit/Receive Mode (Tx at rising, SIOCON.4 = 1) 17 FUNCTION DESCRIPTION Figure 17-1. Voltage Booster Block Diagram Figure 17-2. Pin Connection Example 18 Page 19 Page Page Page Page Page Page Page Figure 19-4. Stop Mode (Main) Release Timing Initiated by Interrupts Figure 19-5. Stop Mode (Sub) Release Timing Initiated by Interrupts Page Page Page Page Page Page Page 20 The S3C8245/C8249 microcontroller is currently available in 80-pin-QFP/TQFP package. Figure 20-1. Package Dimensions (80-QFP-1420C) 80-QFP-1420C 80-TQFP-1212 Figure 20-2. Package Dimensions (80-TQFP-1212) 21 S3P8245/P8249 OTP S3C8245/P8245/C8249/P8249 21-2 S3P8245/P8249 80-QFP (Top View) Figure 21-1. S3P8245/P8249 Pin Assignments (80-QFP) Package Page Page Page Page Page Page 22 Figure 22-1. SMDS Product Configuration (SMDS2+) TB8245/8249 Figure 22-2. TB8245/8249 Target Board Configuration + Page Page DEVELOPMENT TOOLS S3C8245/P8245/C8249/P8249 40-Pin DIP Connector 22-6 40-Pin DIP Connector Figure 22-3. 40-Pin Connectors (J101, J102) for TB8245/8249 Target Board 40-Pin DIP Connector Figure 22-4. S3E8240 Cables for 80-QFP Package Target System J102 41 42 J101 1 2