UPD78F1502AGK-GAK-AX Datasheet, PDF (449/1031 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcontrollers

78K0R/Lx3
CHAPTER 12 OPERATIONAL AMPLIFIER (μ PD78F150xA only)
12.4 Operational Amplifier Operations
The operational amplifiers 0 to 2 have the following mode.
• Single AMP mode (operational amplifiers 0 to 2)
12.4.1 Single AMP Mode
In single amplifier mode, the difference in potential of analog voltages input from two pins (AMPn− and AMPn+ pins) is
amplified and the amplified voltage is output from the AMPnO pin. The gain is determined by externally connecting a
resistor or the like.
The amplified voltage can be used as an analog input of the A/D converter, because the AMPnO pin is alternatively
used with analog input pin of the A/D converter.
The procedure for starting operation in single amplifier mode is described below.
<1> Set bit 5 (ADCEN) of peripheral enable register 0 (PER0) to 1 to start the supply of the input clock to the operational
amplifier.
<2> Use the A/D port configuration register (ADPC) to set the pins (AMPn−, AMPn+, AMPnO) to be used in single
amplifier mode as analog inputs.
<3> Use the port mode register x (PMx) to set the pins (AMPn−, AMPn+, AMPnO) to be used in single amplifier mode to
input mode.
<4> Set (1) the OAENn bit of operational amplifier control register (OAC) and enable operation in single amplifier mode.
<5> Use software to wait until the operational amplifier stabilizes (turn-on time: 20 μs (MAX.)).
Caution To use as an input of the A/D converter a voltage that has been amplified in single amplifier mode,
enable operation in single amplifier mode before selecting an analog input channel by using the ADS
register.
Remark 78K0R/LF3:
n = 0, 1, x = 2
78K0R/LG3, 78K0R/LH3: n = 0 to 2, x = 2, 15
R01UH0004EJ0501 Rev.5.01
433
Jun 20, 2011