5 bus interface pin – NEC V850/SF1 User Manual

Page 26

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CHAPTER 4 CAUTIONS

User’s Manual U15447EJ1V0UM

26

4.5

Bus Interface Pin

The operation of the pin for the bus interface differs between the emulator and the target device as follows.

Table 4-1. Bus Interface Pin Operation List (1/2)

(a) During break

Internal Memory

External Memory

Memory Used by

Emulator

Internal

ROM

Internal RAM

Internal

Peripheral I/O

Emulation RAM

Target System

Pin Name

F

R

W

R

R

W

R

W

R

W

R

W

A16 to A21

Hold the last accessed address

Active

Active

AD0 to AD15

Hi-Z

Active

Active

ASTB

H

Active

Active

R/W

H

Active

Active

DSTB

H

H

Active

LBEN

H

Active

Active

UBEN

H

Active

Active

WAIT

Invalid

Maskable

Maskable

HLDRQ

Maskable

Maskable

Maskable

HLDAK

H or L

H or L

H or L

WRL

H

H

H

Note

WRH

H

H

H

Note

RD

H

H

Note

H

Note Active

Caution When accessing an FCAN register with the external memory expanded, a bus cycle for FCAN

access is generated in AD0 to AD15 and A16 to A21. However, R/W, DSTB, LBEN, UBEN, WRL,

WRH, and RD are inactive.

Remarks 1. F:

Fetch

R:

Read

W:

Write

2. H:

High-level output

L:

Low-level output

Hi-Z:

High-impedance

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