NEC PD75402A, PD75P402 - page 80

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CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS

5.4.4 Examples of Basic Interval Timer Applications

Example 1. In this example the basic interval timer is enabled, and the interrupt generation interval is set to 1.95

ms (at 4.19 MHz operation).

SEL MB15

MOV A, #1111B

MOV BTM,A ; Setting and start

EI ; Enable interrupts

EI IEBT ; Enable BT interrupts

Example 2. Example of watchdog timer application

When used as a watchdog timer, the basic interval timer’s function of generating an interrupt (INTBT)

at set intervals is used.

First, the standard time generated by the basic interval timer is decided.

Next, the program is divided into a number of modules whose processing should terminate within

the standard time, and the counter (BT) and interrupt request flag (IRQBT) are cleared each time a

module ends. A program is written such that an interrupt (INTBT) is not generated if operation is

normal. In other words, if an interrupt is generated, this is interpreted as indicating inadvertent

program looping.

The interrupt generation interval is set to 31.25 ms (in 4.19 MHz operation) so that the processing

time for each module is less than 31.25 ms.

Initial

Setting

➤

MOV A, #1011B

MOV BTM, A

Module 1 Processing termination within 31.25 ms

➤

➤

MOV A, #1011B

MOV BTM, A

Module 2 Processing termination within 31.25 ms

➤

SEL MB15 ; or CLR1 MBE

MOV A, #1011B

MOV BTM, A ; Interval setting and counter start

EI

EI IEBT

………………

Contents

Main USER'S MANUAL PD75402A Page Page PREFACE USER OBJECTIVE COMPOSITION READING LEGEND Page Page Page Page CONTENTS OF FIGURES Fig. No Title Page Fig. No. Title Page Table No. Title Page CHAPTER 1. GENERAL 2 1.1 OUTLINE OF FUNCTIONS Page Page 5 1.4 BLOCK DIAGRAM PD75P402. Remarks Parentheses for the Page 7 (2) PROM mode PD75P402C/CT 8 1.5.2 44-Pin Plastic QFP ( 10mm) (1) Normal operating mode PD75P402s VPP is to be set to the GND potential. PD75P402 and the printed circuit board commonly in the Remarks Parentheses for the 9 (2) PROM mode CHAPTER 2. PIN FUNCTIONS 11 2.1 Remarks 1. In the PD75402A PIN FUNCTION LIST 2.1.1 Port Pin List Table 2-1 Port Pin List 12 2.1.2 List of Pins Other Than Port Pins Table 2-2 List of Pins Other than Port Pins PD75P402 and the printed circuit board commonly, the NC pin should be connected directly to VSS. Remarks For the status of each pin at reset, see CHAPTER 8 RESET FUNCTION. *If using the Page Page Page Page Page V V Type D P.U.R. P-ch P.U.R. enable IN P-ch N-ch V Type D V OUT data output disable P-ch IN/OUT data output disable IN/OUT data output disable Page CHAPTER 3. FEATURES OF ARCHITECTURE AND MEMORY MAP 22 Table 3-1 Data Memory Configuration and Address Range in Each Addressing Mode 23 Table 3-2 Addressing Mode List Page Page Page Page Page 29 Table 3-4 PD75402A I/O Map (1/2) Remarks 1. IE is an interrupt enable flag. 2. IRQ is an interrupt request flag. 30 Table 3-4 PD75402A I/O Map (2/2) CHAPTER 4. INTERNAL CPU FUNCTIONS ~ ~~ ~ Page Page Page Page Page 38 CHAPTER 4. INTERNAL CPU FUNCTIONS Fig. 4-8 Data Saved to Stack Memory Fig. 4-9 Data Restored from Stack Memory Page Page CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS Page 43 Fig. 5-2 Configuration of Ports 0 and 1 Page 45 Fig. 5-4 Configuration of Ports 2 and 6 Internal Bus Output Latch Page Page Page Page 50 Table 5-3 Operations with Input/Output Port Handling Instructions Page Page Page Page Page 56 Fig. 5-11 Processor Clock Control Register Format s) as CPU clock. Note When using a calue of fXX such that 4.19 MHz < fXX 5.0 MHz, if maximum speed mode : fXX/4 (PCC1, PCC0 = 11) is set as CPU clock frequency, 1 machine cycle is less than 0.95 Page Page Page Page Page Page Page Page Page Page () Page Page Page Page 72 Fig. 5-24 Serial Interface Block Diagram Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page 109 Fig. 5-46 ACKD Operation (a) When ACK signal is output in 9th SCK clock interval Fig. 5-47 BSYE Operation (c) Clearing timing when transfer start directive is given during busy state (b) When ACK signal is output after 9th SCK clock interval HSCK SB0 111 Table 5-8 Signals in SBI Mode (2/2) 1 2 7 8 1 2 7 8 9 10 SB0 SCK Page 114 Fig. 5-49 Address Transmission form Master Device to Slave Device (WUP = 1) 115 Fig. 5-50 Command Transmission from Master Device to Slave Device 116 Fig. 5-51 Data Transmission from Master Device to Slave Device 117 Fig. 5-52 Data Transmission from Slave Device to Master Device Page Page Page Page Page Page Page CHAPTER 6. INTERRUPT FUNCTIONS 127 CHAPTER 6. INTERRUPT FUNCTIONS Fig. 6-1 Interrupt Control Circuit Block Diagram Page 6.3 INTERRUPT CONTROL CIRCUIT HARDWARE Page 131 CHAPTER 6. INTERRUPT FUNCTIONS Fig. 6-4 INT0 Noise Elimination Circuit Input/Output Timing Page Page Page Page Page Page Page Page CHAPTER 7. STANDBY FUNCTION Page Page Page CHAPTER 8. RESET FUNCTION 147 CHAPTER 8. RESET FUNCTION Table 8-1 State of Hardware after Reset *The contents of data memory addresses 038H to 03DH are made undefined by RESET input. CHAPTER 9. INSTRUCTION SET Page Page Page Page 153 2. Accumulator operation instructions 3. Increment/decrement instructions 4. Compare instructions () 154 Note Instruction Group Page Page 157 2. Accumulator operation instructions 3. Increment/decrement instructions 4. Compare instruction 158 2. Branch instructions 3. I/O instructions 4. CPU control instructions MOV A, #n4 MOV rp, #n8 MOV A, @HL MOV @HL, A MOV A, mem MOV XA, mem MOV mem, A MOV mem, XA XCH A, @HL XCH A, mem XCH XA, mem XCH A, reg1 MOVT XA, @PCXA ADDS A, #n4 ADDS A, @HL ADDC A, @HL AND A, @HL Page RORC A NOT A Page Page Page Page Page BR addr BR $addr BRCB !caddr CALLF !faddr RET RETS RETI PUSH rp POP rp Page IN A, PORTn OUT PORTn, A Page 177 PD75402A and PD75402A. Since the 178 179 The following development tools are available for system development using the ~ PD75402A: Language Processor PROM Writing Tools Page 181 Development Tool Configuration