SPRUJ53D April 2024 – April 2026 TMS320F28P550SG , TMS320F28P550SJ , TMS320F28P559SG-Q1 , TMS320F28P559SJ-Q1
The opens/shorts detection circuit (OSDETECT) can be used to detect pin faults in the system. The circuit connects to the ADC input after the channel select multiplexer but before the S+H circuit as shown in Figure 15-29.
Figure 15-29 Opens/Shorts Detection Circuit
The circuit can be operated by writing a value to the DETECTCFG field in the ADCOSDETECT register from the Analog Subsystem. This causes the circuit to source a voltage onto the input during the S+H phase of any conversion. The voltage and drive strength of the OSDETECT circuit for different DETECTCFG settings is given in Table 15-8.
| ADCOSDETECT. DETECTCFG | Source Voltage | S4 | S3 | S2 | S1 | Drive Impedance |
|---|---|---|---|---|---|---|
| 0 | Off | Open | Open | Open | Open | Open |
| 1 | Zero Scale | Closed | Open | Open | Closed | 5K || 7K |
| 2 | Full Scale | Open | Closed | Closed | Open | 5K || 7K |
| 3 | 5/12 VDDA | Open | Closed | Open | Closed | 5K || 7K |
| 4 | 7/12 VDDA | Closed | Open | Closed | Open | 5K || 7K |
| 5 | Zero Scale | Open | Open | Open | Closed | 5K |
| 6 | Full Scale | Open | Open | Closed | Open | 5K |
| 7 | Zero Scale | Closed | Open | Open | Open | 7K |
Additionally, configure the REFCONFIGB register for the corresponding ADC channel to enable TESTANA1 to enable opens/shorts detection.