7470 Datasheet, PDF (38/47 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
7470/7471 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
PROM READING AND WRITING
Reading
To read the PROM, set the CE and OE pins to “L” level. Input the
address of the data (A0–A14) to be read and the data will be out-
put to the I/O pins (D0–D7). The data I/O pins will be floating when
either the CE or OE pin is in the “H” state.
Writing
To write to the PROM, set the OE pin to “H” level. The CPU will en-
ter the program mode when VPP is applied to the VPP pin. The
address to be written to is selected with pins A0–A14, and the
data to be written is input to pins D0–D7. Set the CE pin to “L” level
to begin writing.
Notes on Writing
• M37470E4, M37471E4
When using a PROM programmer, the address range should be
between 600016 and 7FFF16. Addresses 000016 to 5FFF16 can-
not be written to or read from correctly.
• M37470E8, M37471E8
When using a PROM programmer, the address range should be
between 400016 and 7FFF16. When data is written between ad-
dresses 000016 and 7FFF16, fill addresses 000016 to 3FFF16
with FF16.
Erasing
Data can only erased on the M37471E8SS ceramic package,
which includes a window. To erase data on this chip, use an ultra-
violet light source with a 2537 Angstrom wave length. The
minimum radiation power necessary for erasing is 15W·s/cm².
NOTES ON HANDLING
(1) Sunlight and fluorescent light contain wave lengths capable of
erasing data. For ceramic package types, cover the transpar-
ent window with a seal (provided) when this chip is in use.
However, this seal must not contact the lead pins.
(2) Before erasing, the glass should be cleaned and stains such
as finger prints should be removed thoroughly. If these stains
are not removed, complete erasure of the data could be pre-
vented.
(3) Since a high voltage (12.5 V) is used to write data, care should
be taken when turning on the PROM programmer’s power.
(4) For the programmable microcomputer (shipped in One Time
PROM version), Mitsubishi does not perform PROM write test
and screening in the assembly process and following pro-
cesses. To improve reliability after write, performing write and
test according to the flow below before use is recommended.
Writing with PROM programmer
Screening (Caution) (Leave at 150°C for 40 hours)
Verify test with PROM programmer
Function check in target device
Table 3. I/O signal in each mode
Mode
Pin
CE
OE
Read-out
VIL
VIL
Output disable
VIL
VIH
Programming
VIL
VIH
Programming verify
VIH
VIL
Program disable
VIH
VIH
Note : VIL and VIH indicate a “L” and “H” input voltage, respectively.
Caution : Since the screening temperature is higher than storage
temperature, never expose to 150°C exceeding 100
hours.
VPP
VCC
Data I/O
VCC
VCC
Output
VCC
VCC
Floating
VPP
VCC
Input
VPP
VCC
Output
VPP
VCC
Floating
37