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.

7.3Other 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).

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