UPD784021 datasheet(6/90 Pages) NEC

6 / 90 page

mPD784020, 784021

1. DIFFERENCES BETWEEN

mPD784026 SUB-SERIES

The only difference between the

mPD784020, mPD784021, mPD784025, and mPD784026 is their capacity of

internal memory, port functions, and part of their packages.

The

mPD78P4026 is produced by replacing the masked ROM in the mPD784025 or mPD784026 with 64K-byte one-

time PROM or EPROM. Table 1-1 shows the differences between these products.

Table 1-1 Differences between the

mPD784026 Sub-Series

Product

Item

Internal ROM

Internal RAM

P40-P47

P50-P57

P60-P63

P64, P65

Package

mPD784020

None

512 bytes

80-pin plastic QFP

(14

¥ 14 mm)

mPD784021

2048 bytes

80-pin plastic QFP

(14

¥ 14 mm)

80-pin plastic

TQFP (fine pitch)

(12

¥ 12 mm)

mPD784025

48K bytes

(masked ROM)

mPD784026

64K bytes

(masked ROM)

mPD78P4026

64K bytes

(one-time PROM

or EPROM)

80-pin plastic QFP

(14

¥ 14 mm)

80-pin ceramic

WQFN

(14

¥ 14 mm)

Functions only as an address/data bus

Functions only as an address bus

Can be switched to an output-only port

or address bus in units of 2 bits, by

using software

Functions only as the RD or WR pin

Can be switched to a general-purpose port or address/data

bus, by using software

Can be switched to a general-purpose port or address bus in

units of 2 bits, by using software

Functions as the RD or WR pin when the local bus interface

is used. Functions as a general-purpose port in other cases.

80-pin plastic QFP (14

¥ 14 mm)

UPD784021 Datasheet(PDF) 6 Page - NEC

UPD784021 Datasheet(HTML) 6 Page - NEC

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