135
4554 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
PRELIMINAR
Y
Notice:
This
is not
a final
specification.
Some
parametric
limits
are
subject
to change.
(1) PROM mode
The built-in PROM version has a PROM mode in addition to a nor-
mal operation mode. The PROM mode is used to write to and read
from the built-in PROM.
In the PROM mode, the programming adapter can be used with a
general-purpose PROM programmer to write to or read from the
built-in PROM as if it were M5M27C256K.
Programming adapter is listed in Table 26. Contact addresses at
the end of this data sheet for the appropriate PROM programmer.
Writing and reading of built-in PROM
Programming voltage is 12.5 V. Write the program in the PROM of
the built-in PROM version as shown in Figure 74.
(2) Notes on handling
A high-voltage is used for writing. Take care that overvoltage is
not applied. Take care especially at turning on the power.
For the One Time PROM version shipped in blank, Mitsubishi
Electric corp. does not perform PROM writing test and screening
in the assembly process and following processes. In order to im-
prove reliability after writing, performing writing and test
according to the flow shown in Figure 74 before using is recom-
mended (Products shipped in blank: PROM contents is not
written in factory when shipped).
(3) Difference between Mask ROM version and
One Time PROM version
Mask ROM version and One Time PROM version have some differ-
ence of the following characteristics within the limits of an electrical
property by difference of a manufacture process, built-in ROM, and
a layout pattern.
a characteristic value
a margin of operation
the amount of noise-proof
noise radiation, etc.,
Accordingly, be careful of them when swithcing.
Fig. 60 PROM memory map
Fig. 61 Flow of writing and test of the product shipped in blank
Microcomputer
M34554EDFP
Name of Programming Adapter
PCA7448
Table 26 Programming adapter
Address
000016
3FFF16
7FFF16
1
11
D4
D3
D2
D1
D0
High-order 5 bits
1
11
D4
D3
D2
D1
D0
Low-order 5 bits
400016
Writing with PROM programmer
Screening (Leave at 150
°C for 40 hours) (Note)
Verify test with PROM programmer
Function test in target device
Since the screening temperature is higher
than storage temperature, never expose the
microcomputer to 150
°C exceeding 100
hours.
Note: