HD404374FT datasheet(110/161 Pages) RENESAS

110 / 161 page

HD404374/HD404384/HD404389/HD404082/HD404084 Series

Rev.5.00, Sep.11.2003, page 110 of 161

terminal. If power source noise is noticed, insert an appropriate capacitor between the GND power

sources depending on the noise generated. In case of high frequency noise , insert a capacitor of low

inductance.

(d) For stable writing and reading operation, insert the IC into the socket adapter and check the input

waveform, timing and noise near the R/W, CS, address and data terminals. Particularly, since recent

ICs have increased in speed, caution should be exercised against the noise to the power source or

address due to crosstalk from the output data terminal. To avoid these problems, inserting a low

inductance capacitor between the GND and power source or inserting a damping resistance to the

output data terminal is effective.

(e) Particularly, when a multiple PROM writer is used, perform above items (a), (b), (c), and (d) assuming

all ICs inserted into the socket adapter.

(f) In the case of a multiple PROM writer, when an unacceptable result is noticed during a blank check

performed to prevent erroneous writing due to improper electrical connection of the power source, etc.,

rewriting is impossible unless every writing process can be stopped. Therefore, the potential increases

due to erroneous writing because of improper connection. Be sure to check the electrical connection

between the PROM writer and socket adapter and IC.

(g) If any abnormality is noticed while checking a written program, consult our technical staff.

Programming of Built-in programmable ROM

The MCU can stop its function as an MCU in PROM mode for programming the built-in PROM.

PROM mode is set up by setting the RESET and MO terminals to “Low” level and the TEST terminal to

“Vpp” level.

Writing and reading specifications of the PROM are the same as those for the commercial EPROM27256.

Using a socket adapter for specific use of each product, programming is possible with a general-purpose

PROM writer.

Since an instruction of the HMCS400 series is 10 bits long, a conversion circuit is incorporated to adapt the

general-purpose PROM writer. This circuit splits each instruction into five lower bits and five higher bits

to write from or read to two addresses. This enables use of a general-purpose PROM. For instance, to

write to a 16kword of built-in PROM writer with a general-purpose PROM, specify 32kbyte address

($0000-$7FFF). An example of PROM memory map is shown in figure 70.

HD404374FT Datasheet(PDF) 110 Page - Renesas Technology Corp