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CHAPTER 12 A/D CONVERTER
User’s Manual U19780EJ2V0UD
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(4) 12-bit A/D conversion result register (ADCR)
This register is a 16-bit register that stores the A/D conversion result. The higher 4 bits are fixed to 0. Each time A/D
conversion ends, the conversion result is loaded from the successive approximation register. The higher 4 bits of the
conversion result are stored in FF19H and the lower 8 bits are stored in FF18H.
ADCR can be read by a 16-bit memory manipulation instruction.
Reset signal generation clears this register to 0000H.
Figure 12-8. Format of 12-Bit A/D Conversion Result Register (ADCR)
Symbol
Address: FF18H, FF19H After reset: 0000H R
FF19H
FF18H
0
0
0
0
ADCR
Caution When writing to the A/D converter mode register (ADM), analog input channel specification register
(ADS), and A/D port configuration register (ADPC), the contents of ADCR may become undefined.
Read the conversion result following conversion completion before writing to ADM, ADS, and ADPC.
Using timing other than the above may cause an incorrect conversion result to be read.
(5) 8-bit A/D conversion result register (ADCRH)
This register is an 8-bit register that stores the A/D conversion result. The higher 8 bits of 12-bit resolution are stored.
ADCRH can be read by an 8-bit memory manipulation instruction.
Reset signal generation clears this register to 00H.
Figure 12-9. Format of 8-Bit A/D Conversion Result Register (ADCRH)
Symbol
Address: FF19H After reset: 00H R
FF19H
FF18H
0
0
0
0
ADCRH
ADCRH
Note
Note
When address FF19H is read, the data of ADCRH (the lower 4 bits of FF19H and the higher 4 bits of FF18H) is
read.
Caution When writing to the A/D converter mode register (ADM), analog input channel specification register
(ADS), and A/D port configuration register (ADPC), the contents of ADCRH may become undefined.
Read the conversion result following conversion completion before writing to ADM, ADS, and ADPC.
Using timing other than the above may cause an incorrect conversion result to be read.