SFFS277 November 2023 TMS320F280033 , TMS320F280034 , TMS320F280034-Q1 , TMS320F280036-Q1 , TMS320F280036C-Q1 , TMS320F280037 , TMS320F280037-Q1 , TMS320F280037C , TMS320F280037C-Q1 , TMS320F280038-Q1 , TMS320F280038C-Q1 , TMS320F280039 , TMS320F280039-Q1 , TMS320F280039C , TMS320F280039C-Q1
The opens/shorts detection circuit (OSDETECT) can be used to detect ADC input channel 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 6-8. Error response, diagnostic testability, and any necessary software requirements are defined by the software implemented by the system integrator.
The circuit can be operated by writing a value to the DETECTCFG field in the ADCOSDETECT register. This will cause 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 6-1. For additional details on implementing this diagnostic, see the Opens/Shorts Detection Circuit (OSDETECT) section in the TMS320F28003x Microcontrollers Technical Reference Manual.
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 |