UPD78F1502AGK-GAK-AX Datasheet, PDF (412/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 10 12-BIT A/D CONVERTER (μ PD78F150xA),
10-BIT A/D CONVERTER (μ PD78F151xA)
Cautions 2. To use voltage reference output to the positive reference voltage of the A/D converter, be sure to
set VRON to 1 after setting VRSEL to 1.
3. Do not change the output voltage of the reference voltage by using VRGV during the voltage
reference operation (VRON = 1).
Remark The combinations of the selectable reference voltage supplies (positive side, negative side) of the A/D
converter are as follows, according to the ADREF, VRSEL and VRON settings.
ADREF
VRSEL
0
0
0
1
1
0
1
1
Table 10-3. Settings of ADREF, VRSEL and VRON
VRON
0
1
0
1
Positive reference voltage of A/D
converter (ADREFP)
AVREFP
VREFOUT (VR output)
AVREFP
VREFOUT (VR output)
Negative reference voltage of A/D
converter (ADREFM)
AVSS
AVSS
AVREFM
AVREFM
<R>
(5) 12-bit A/D conversion result register (ADCR) (μ PD78F150xA only)
This register is a 16-bit register that stores the A/D conversion result in the select mode. 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 FFF1FH and the lower 8 bits are stored in the FFF1EH.
ADCR can be read by a 16-bit memory manipulation instruction.
Reset signal generation clears this register to 0000H.
Figure 10-10. Format of 10-bit A/D Conversion Result Register (ADCR)
Address: FFF1EH, FFF1FH After reset: 0000H R
Symbol
FFF1FH
FFF1EH
ADCR 0
0
0
0
Caution When writing to 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.
R01UH0004EJ0501 Rev.5.01
396
Jun 20, 2011