EFM32WG Datasheet, PDF (730/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

...the world's most energy friendly microcontrollers
field to PAD in DACn_OPAxMUX. In addition the output is configured by the OUTPEN bit-field, located
in DACn_OPAxMUX.
Figure 30.5. Inverting input PGA Overview
POS
+
-
VOUT
VOUT= -(VIN-POS) R2/R1 + POS
VIN _R1
R2
Table 30.3. Inverting input PGA Configuration
OPA bit-fields
OPA Configuration
OPAx POSSEL
POSPADx
OPAx NEGSEL
OPATAP
OPAx RESINMUX
NEXTOUT, NEGPADx, POSPADx
30.3.2.4 Non-inverting PGA
Figure 30.6 (p. 730) shows the non-inverting input configuration. In this mode the negative input is
connected to the resistor ladder by setting the OPAxNEGSEL bit-field to OPATAP in DACn_OPAxMUX.
This setting provides a programmable gain on the negative input, which can be set by choosing the
wanted gain value in the RESSEL bit-field in DACn_OPAxMUX. In addition the OPAxRESINMUX
bit-field must be set to VSS or NEGPAD in DACn_OPAxMUX. The positive input is selected by
the OPAxPOSSEL bit-field, and the output is configured by the OUTPEN bit-field, both located in
DACn_OPAxMUX.
Figure 30.6. Non-inverting PGA Overview
VIN
+
-
VOUT
VOUT= VIN(1+ R2/R1)
R1
R2
Table 30.4. Non-inverting PGA Configuration
OPA bit-fields
OPAx POSSEL
OPAx NEGSEL
OPAx RESINMUX
OPA Configuration
NEXTOUT, POSPADx
OPATAP
VSS, NEGPAD
30.3.2.5 Cascaded Inverting PGA
This mode enables the opamp signals to be internally configured to cascade two or three opamps in
inverting mode as shown in Figure 30.7 (p. 731) . In both cases the positive input will be configured
to signal ground by setting OPAxPOSSEL bit-field to PAD in DACn_OPAx_MUX. When cascaded, the
negative input is connected to the resistor ladder by setting the OPAxNEGSEL bit-field to OPATAP in
DACn_OPAxMUX. The input to the resistor ladder can be configured in the OPAxRESINMUX bit-field
in DAC_nOPAxMUX. The output from OPA0 can be connected to OPA1 to create the second stage
by setting the NEXTOUT bit-field in DACn_OPAxMUX. To complete the stage, OPA1RESINMUX field
must be set to OPA0INP. Similarly, the last stage can be created by setting the NEXTOUT bit-field in
DACn_OPA1MUX and OPA2RESINMUX bit-field to OPA1INP in DACn_OPA2MUX.
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
730
www.energymicro.com