HD404629R Datasheet, PDF (114/157 Pages) Renesas Technology Corp – AS Microcomputer Incorporating a DTMF Generator Circuit

HD404629R Series
ZTAT^TM Microcomputer with Built-in programmable ROM
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 TEST, M0, and M1 terminals to “Low” level and the RESET terminal
to “High” 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 with a general-purpose PROM writer, specify 32kbyte address
($0000-$7FFF).
Notes:
1. When programming with a PROM writer, set up each ROM size to the address given in table b. If it is
programmed erroneously to an address given in Table 33 or later, check of writing of PROM may
become impossible. Particularly, caution should be exercised in the case of a plastic package since
reprogramming is impossible with it. Set the data in unused addresses to $FF.
2. If the indexes of the PROM writer socket, socket adapter and product are not aligned precisely, the
product may break down due to overcurrent. Be sure to check that they are properly set to the writer
before starting the writing process.
3. Two levels of program voltages (VPP) are available for the PROM: 12.5 V and 21 V. Our product
employs a VPP of 12.5 V. If a voltage of 21 V is applied, permanent breakdown of the product will
result. The VPP of 12.5 V is obtained for the PROM writer by setting it according to the Intel 27258
specifications.
Writing/verification
Programming of the built-in program ROM employs a high speed programming method. With this method,
high speed writing is effected without voltage stress to the device or without damaging the reliability of the
written data.
For precautions for PROM writing procedure, refer to section 2, "Characteristics of ZTAT^TM
Microcomputer's Built-in Programmable ROM and precautions for its Applications."
112