UPD784915AGF View Datasheet(PDF) - NEC => Renesas Technology

Part Name

Description

Manufacturer

UPD784915AGF

16-BIT SINGLE-CHIP MICROCONTROLLERS

NEC => Renesas Technology 

µPD784915A, 784916A

3.1.2 Other CPU registers

(1) Program counter

The program counter of the µPD784916A is 20 bits wide. The value of the program counter is automatically

updated as the program is executed.

19

0

PC

(2) Program status word

This is a register that holds the various statuses of the CPU. Its contents are automatically updated as the program

is executed.

15 14 13 12 11 10 9 8

PSWH UF RBS2 RBS1 RBS0

PSW

7

PSWL S

6543210

Z

Note

RSS

AC

IE

P/V

0

CY

Note The RSS flag is provided to maintain compatibility with the microcomputers in the 78K/III Series. Always

clear this flag to 0 except when the software of the 78K/III Series is used.

(3) Stack pointer

This is a 24-bit pointer that holds the first address of the stack.

Be sure to write 0 to the higher 4 bits.

23

20

0

SP 0 0 0 0

3.2 Memory Space

The µPD784916A can access a 64K-byte memory space.

The addresses of the internal ROM and internal data areas are as follows:

Table 3-1. Memory Space

Part Number

µPD784915A

µPD784916A

Internal ROM Area

0000H-BFFFH

0000H-F7FFH

Internal Data Area

FA00H-FFFFH

Caution

Some products in the 78K/IV Series can access up to 1 Mbyte of memory space in an address

expansion mode which is set by the LOCATION instruction. However, the memory space of the

µPD784916A is 64K bytes (0000H through FFFFH). Therefore, be sure to execute the LOCATION

0 instruction immediately after reset to set the memory space to 64 Kbytes (the LOCATION

instruction cannot be used more than once).

20

Share Link: