SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
The following analog subsystem block diagrams show the connections between the different integrated analog modules to the device pins. These pins fall into two categories: analog module inputs/outputs and reference pins.
The reference pins, VREFHIA to VREFHID and VREFLOA to VREFLOD, can be used to externally supply the reference to the ADC. VREFHIA can also be used to supply the reference voltage to DAC A and DAC B and VREFHIB can be used to supply the reference to DAC C.
The analog module input and outputs are all ADC inputs by default. The pins that connect to CMPSS inputs can be used for the CMPSS without further action and without preventing use as an ADC input simultaneously. DAC outputs must be enabled; this prevents the channel from simultaneously being used as an ADC input (but the ADC can be used to sample the DAC output voltage, if desired).
The VDAC reference pin can be used to set an alternate range for DAC A, DAC B, and DAC C and for the DACs inside the CMPSS modules (the CMPSS DACs are referenced to VDDA and VSSA by default). Using this pin as a reference prevents the channel from being used as an ADC input (but the ADC can be used to sample the VDAC voltage, if desired). The choice of reference is configurable per-module for each CMPSS or buffered DAC, and the selection is made using the module’s configuration registers.
The following notes apply to all packages:
Signal Name | Description |
---|---|
ADCINAx | ADC A Input |
ADCINBx | ADC B Input |
ADCINDx | ADC D Input |
CMPINxP | Comparator subsystem positive input |
CMPINxN | Comparator subsystem negative input |
DACOUTx | Buffered DAC Output |
TEMP SENSOR | Internal temperature sensor |
VDAC | Optional external reference voltage for on-chip DACs. There is a 100pF capacitor to VSSA on this pin whether used for ADC input or DAC reference that cannot be disabled. If this pin is being used as a reference for the on-chip DACs, place at least a 1µF capacitor on this pin. |
Module | Reference Option | Configured Where? | Register | Driverlib Function | Notes |
---|---|---|---|---|---|
ADC | External or Internal | Not Configurable | N/A | N/A | VREFHI must always be driven externally on this device. |
Buffered DAC | VREFHI or VDAC | DAC Module | DacxRegs. DACCTL.bit.DACREFSEL | DAC_CTL_DACREFSEL | |
External or Internal | Not Configurable | N/A | N/A | VREFHI must always be driven externally on this device. | |
CMPSS DACs | VDDA or VDAC | CMPSS Module | CmpssxRegs. COMPDACCTL.bit.SELREF | CMPSS_COMPDACCTL_SELREF |