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7.2 MCUs Do Not Function Normally
The program operates normally on the emulator, but when the MCU that has normally been written
is attached the same program does not necessarily operate in the same manner. The differences
between actual MCUs and the emulator are listed below.
(1) About ROM area
With the emulator, the area where the program has not been read serves as NOP instruction (00h),
but the MCU which has been written by the PROM programmer serves as FFh. Therefore the
program happens to appear functioning normally even though it may have gone wild.
(2) About the initial value of the register
With the emulator, the initial value of the register is set to register Z to display the contents of RAM
according to the area for referencing. However, with the actual MCU, the register Z is indefinite
after resetting. For this, if the register Z is not set, the contents of RAM may not be read out
properly.
(3) About oscillations
The emulator is operated by the external clock on the MCU board, while the actual MCU is
operated by the oscillator on the target system. For this, when the oscillator circuit on the target
system does not oscillate properly, the MCU does not function normally.
(4) About differences of the characteristics
The emulator and the actual MCU may differ in characteristics. Consult the user's manuals of the
MCU and the MCU board to check for differences in the characteristics again.
7.3 Other Precautions
(1) About the Recommended PROM Programmers
As MCUs are not totally equal to EPROM, there are some PROM programmer that can not be used
depending on MCU type. The recommended PROM programmers we have verified are listed in
this user's manual. We have verified that those PROM programmers can be used to write programs
without problem.
The other PROM programmers which can set programming area might be used as long as they
pass the verification check, however, we do not assure that they work properly.
Note:
No matter which type of PROM programmer you use, it is necessary to verify completion of
programming by executing screening, etc. that are stipulated for each MCU used.
(2) About Reading Out of Device Identification Code
Please do not use the PROM programmer's device identification code*
1
readout function.
Using this function may break down the MCU. The device identification code is included in
EPROM to indicate the manufacturer code and device code.
*
1
Depending on PROM programmer manufacturers, this may be referred to by another name (e.g.
ID code).