41.8.3 OPAMP Control x

Name:	OPAMPCTRLx
Offset:	0x04+4*x, [x=0..2]
Reset:	0x00000080
Property:	PAC Write-Protection


Bit	31	30	29	28	27	26	25	24

Access
Reset


Bit	23	22	21	20	19	18	17	16
		MUXNEG[2:0]				MUXPOS[2:0]
Access		R/W	R/W	R/W		R/W	R/W	R/W
Reset		0	0	0		0	0	0


Bit	15	14	13	12	11	10	9	8
	POTMUX[2:0]			RES1MUX[1:0]		RES1EN	RES2VCC	RES2OUT
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
	ONDEMAND	RUNSTDBY		BIAS[1:0]		ANAOUT	ENABLE
Access	R/W	R/W		R/W	R/W	R/W	R/W
Reset	0	0		0	0	0	0

Bits 22:20 – MUXNEG[2:0] Negative Input Mux Selection

Selection on negative input for operational amplifier x.


Value	OPAMPx	Name	Description
0x0	x=0,1,2	OAxNEG	Negative I/O pin
0x1	x=0,1,2	OAxTAP	Resistor ladder x taps
0x2	x=0,1,2	OAxOUT	OPAMPx output
0x3	x=0,1	DAC	DAC output
0x3	x=2	OA0NEG	Negative I/O pin OPA0
0x4	x=0,1	Reserved
0x4	x=2	OA1NEG	Negative I/O pin OPA1
0x5	x=0,1	Reserved
0x5	x=2	DAC	DAC output
0x6	x=0,1,2	Reserved
0x7	x=0,1,2	Reserved

Bits 18:16 – MUXPOS[2:0] Positive Input Mux Selection

Selection on positive input for operational amplifier x.


Value	OPAMPx	Name	Description
0x0	x=0,1,2	OAxPOS	Positive I/O pin
0x1	x=0,1,2	OAxTAP	Resistor ladder x taps
0x2	x=0	DAC	DAC output
	x=1	OA0OUT	OPAMP0 output
	x=2	OA1OUT	OPAMP1 output
0x3	x=0,1,2	GND	Ground
0x4	x=0,1	Reserved
0x4	x=2	OA0POS	Positive I/O pin OPA0
0x5	x=0,1	Reserved
0x5	x=2	OA1POS	Positive I/O pin OPA1
0x6	x=0,1	Reserved
0x6	x=2	OA0TAP	Resistor ladder 0 taps
0x7	x=0,1,2	Reserved

Bits 15:13 – POTMUX[2:0] Potentiometer selection

Resistor selection bits control a numeric potentiometer with eight fixed values.


Value	R1	R2	Gain = R2/R1
0x0	14R	2R	1/7
0x1	12R	4R	1/3
0x2	8R	8R	1
0x3	6R	10R	1 + 2/3
0x4	4R	12R	3
0x5	3R	13R	4 + 1/3
0x6	2R	14R	7
0x7	R	15R	15

Bits 12:11 – RES1MUX[1:0] Resistor 1 Mux

These bits select the connection of R1 resistor of the potentiometer.


Value	OPAMPx	Name	Description
0x0	x=0,1,2	OAxPOS	Positive inout of OPAMPx
0x1	x=0,1,2	OAxNEG	Negative input of OPAMPx
0x2	x=0	DAC	DAC output
	x=1	OA0OUT	OPAMP0 output
	x=2	OA1OUT	OPAMP1 output
0x3	x=0,1,2	GND

Bit 10 – RES1EN Resistor 1 Enable

Value	Description
0	R1 disconnected from RES1MUX.
1	R1 connected to RES1MUX.

Bit 9 – RES2VCC Resistor ladder To VCC

Value	Description
0	Swith open.
1	Switch closed.

Bit 8 – RES2OUT Resistor ladder To Output

Value	Description
0	Swith open.
1	Switch closed.

Bit 7 – ONDEMAND On Demand Control

The On Demand operation mode allows the OPAMPx to be enabled or disabled, depending on other peripheral requests.

Value	Description
0	The OPAMPx is always on, if enabled.
1	The OPAMPx is enabled when a peripheral is requesting the OPAMPx to be used as an input. The OPAMPx is disabled if no peripheral is requesting it as an input.

Bit 6 – RUNSTDBY Run in Standby

This bit controls how the OPAMPx behaves during standby sleep mode:

Value	Description
0	The OPAMPx is disabled in standby sleep mode.
1	The OPAMPx is not stopped in standby sleep mode. If OPAMPCTRLx.ONDEMAND=1, the OPAMPx will be running when a peripheral is requesting it as an input. If OPAMPCTRLx.ONDEMAND=0, OPAMPx will always be running in standby sleep mode.

Bits 4:3 – BIAS[1:0] Bias Selection

These bits are used to select the bias mode.

Value	Name	Description
0x0	Mode 0	Minimum current consumption, but the slowest mode
0x1	Mode 1	Low current consumption, slow speed
0x2	Mode 2	High current consumption, fast speed
0x3	Mode 3	Maximum current consumption but the fastest mode

Bit 2 – ANAOUT Analog Output

This bit controls a switch connected to the OPAMP output.

Value	Description
0	Swith open. No ADC or AC connection.
1	Switch closed. OPAMP output is connected to the ADC or AC input.

Bit 1 – ENABLE Operational Amplifier Enable

Value	Description
0	The OPAMPx is disabled
1	The OPAMPx is enabled

SAM L21