Cautions On Emulation - NEC mPD780973 Series Preliminary User's Manual

13.6 Cautions on Emulation

(1) D/A converter mode register (DAM1)
To perform debugging with an in-circuit emulator (IE-78K0-NS), the D/A converter mode register (DAM1) must
be set. DAM1 is a register used to set a probe board (IE-780974-NS-EM1).
DAM1 is used when the power-fail detection function is used. Unless DAM1 is set, the power-fail detection function
cannot be used. DAM1 is a write-only register.
Because the IE-780974-NS-EM1 uses an external analog comparator and a D/A converter to implement part of
the power-fail detection function, the reference voltage must be controlled. Therefore, set bit 0 (DACE) of DAM1
to 1 when using the power-fail detection function.
Figure 13-12. D/A Converter Mode Register (DAM1) Format
Address: FF89H After Reset: 00H W
Symbol 7
DAM1 0
DACE
0
1
Cautions 1. DAM1 is a special register that must be set when debugging is performed with an in-circuit
emulator. Even if this register is used, the operation of the µ PD780973 Subseries is not
affected. However, delete the instruction that manipulates this register from the program at
the final stage of debugging.
2. Bits 7 to 1 must be set to 0.
(2) A/D converter of IE-780974-NS-EM1
The A/D converter of the IE-780974-NS-EM1 may not satisfy the rating of the first A/D conversion value right after
A/D conversion has been started.
The above applies only to the IE-780974-NS-EM1 and does not affect the operation of the µ PD780973 Subseries.
CHAPTER 13 A/D CONVERTER
6 5
0 0
Disabled
Enabled (when power-fail detection function is used)
4 3 2
0 0 0
Reference Voltage Control
1 0
0 DACE
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