HD404374FT datasheet(109/161 Pages) RENESAS

109 / 161 page

HD404374/HD404384/HD404389/HD404082/HD404084 Series

Rev.5.00, Sep.11.2003, page 109 of 161

ZTAT

TM Microcomputer with Built-in Programmable ROM

Precautions for use of ZTATTM microcomputer with built-in programmable ROM

(1) Precautions for writing to programmable ROM built in ZTATTM microcomputer

In the ZTAT

microcomputer with built-in plastic mold one-time programmable ROM, incomplete

electrical connection between the PROM writer and socket adapter causes writing errors and, makes the

computer unoperatable. To enhance the writing efficiency, attention should be paid to the following points:

(a) Make sure that the socket adapter is firmly fixed to the PROM writer and connected electrically with

each other (neither opened nor shorted), before starting the writing process.

(b) To secure the electrical connection between the contact pin and IC lead, make sure that there is no

foreign substance on the contact pin of the socket adapter, which may cause improper electrical

connection.

connection between the contact pin and IC lead. If the lead is bent, correct the bending and insert it

again.

(d) If any trouble is noticed during a blank check to be performed to prevent erroneous writing due to

improper electrical connection, carry out the writing process again according to above steps (a), (b), and

(c).

(e) During the writing process, do not touch the socket adapter and IC to prevent erroneous writing.

(f) To write continuously in the IC, follow steps (a), (b), (c), (d) and (e).

(g) If a writing error recurs, or the rate of writing errors occur frequently, stop writing and check the PROM

writer, socket adapter, etc. for defects.

(h) If any problem is noticed in the written program or in the program after being left at a high temperature,

consult our technical staff.

(2) Precautions when new PROM writer, socket adapter or IC is used

When a new PROM writer, socket adapter or IC is employed, breakdown of the IC may occur or its writing

may become impossible because the noise, overshoot, timing or other electrical characteristics may be

inconsistent with the assured IC writing characteristics. To avoid such troubles, check the following points

before starting the writing process.

(a) To ensure stable writing operation, check that the VCC of the power supplied to the PROM writer,

power source current capacity of VPP, and current consumption at the time of writing to IC are provided

with sufficient margin.

(b) To prevent breakdown of the IC, check that the power source voltage between GND-VCC and GND-

VPP, and overshoot or undershoot of the power source at the connecting terminal of the socket adapter

are within the ratings. Particularly, if the overshoot or undershoot exceeds the maximum rating, the p-n

connection may be damaged, leading to permanent breakdown. If overshoot or undershoot occurs,

recheck the power source damping resistance of capacity.

socket adapter and check the power noise between the GND-VCC and GND-VPP near the IC connecting

HD404374FT Datasheet(PDF) 109 Page - Renesas Technology Corp