CHAPTER 9 A/D CONVERTER
User’s Manual U18172EJ2V0UD
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(2) Analog input channel specification register (ADS)
This register specifies the input port of the analog voltage to be A/D converted.
ADS can be set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 9-5. Format of Analog Input Channel Specification Register (ADS)
ADS0
ADS1
0
0
0
0
0
0
Analog input channel specification
ANI0
ANI1
ANI2
ANI3
ADS0
0
1
0
1
ADS1
0
0
1
1
0
1
2
3
4
5
6
7
ADS
Address: FF81H After reset: 00H R/W
Symbol
Caution Be sure to clear bits 2 to 7 of ADS to 0.
(3) 10-bit A/D conversion result register (ADCR)
This register is a 16-bit register that stores the A/D conversion result. The higher six bits are fixed to 0. Each
time A/D conversion ends, the conversion result is loaded from the successive approximation register, and is
stored in ADCR in order starting from bit 1 of FF19H. FF19H indicates the higher 2 bits of the conversion result,
and FF18H indicates the lower 8 bits of the conversion result.
ADCR can be read by a 16-bit memory manipulation instruction.
Reset signal generation makes ADCR undefined.
Figure 9-6. Format of 10-Bit A/D Conversion Result Register (ADCR)