NEC PD75402A, PD75P402 - page 48

CHAPTER 4. INTERNAL CPU FUNCTIONS

37

4.6 STACK POINTER (SP) ..... 8 BITS

The

µ

PD75402A uses a static RAM as the stack memory (LIFO format). The 8-bit register holding the top address

information of such a stack memory area is the stack pointer (SP). Fig. 4-7 shows its format.

As the SP’s high-order 3 bits are fixed to 001, the stack area is at the static RAM’s addresses 020H to 03FH.

The SP is decremented before write (save) in the stack memory and is incremented after read (restore) from the

stack memory. Figs. 4-8 and 4-9 show the data saved and restored by each stacking operation.

The SP sets the initial value by the 8-bit data transfer instruction to determine the stack area. It is impossible to

read the content of the SP.

Zero is always written in the SP’s bit 0.

It is recommended to initialize by writing 40H in the SP and use the built-in RAM’s maximum address (03FH) and

beyond as the stack area.

The content of the SP turns indeterminate at RESET input, so it must be initialized to your desired value by the

program initialization routine.

Note The SP of the Evachip packaged on the board for evaluation can address all the areas of 000H to 0FFH unlike

in the

µ

PD75402A. To eliminate such a difference at evaluation, the SP should be set not to access beyond

the range of 020H to 03FH.

Example SP initialize

MOV XA, #40H

MOV SP, XA ; SP ← 40H

Fig. 4-7 Stack Pointer Configuration

Address 76543210 Symbol

F80H 0 0 1 SP4 SP3 SP2 SP1 SP0 SP

↑

0 Fixed

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