TRAVEO™ T2G MCU: How to monitor VDDIO with ADC – KBA237997
Community Translated: TRAVEO™ T2G MCU：ADCでVDDIOを監視する方法 – KBA237997
Analog to Digital Converter (ADC) core reads the VDDIO input as a digital value through AMUXBUS and SARMUX, as shown in Figure 1. AMUXBUS is a bus for monitoring the power supply voltages with an ADC. Basically, AMUXBUS consists of AMUXBUS A and AMUXBUS B. AMUXBUS A is used for VDDIO because AMUXBUS A is for power and AMUXBUS B is for ground. SARMUX decides about which ADC ch. to connect to.
- The HSIOM_MONITOR_CTL_0 register is used to control the connectivity of power/ground pads to either AMUXBUS_A or AMUXBUS_B respectively. For details, see Section “Voltage Monitoring” in the Architecture Technical Reference Manual.
Figure 1 ADC diagram for monitoring VDDIO
- If VDDIO is higher than the ADC reference voltage (for example, 3.3 V), use Reference Buffer for voltage division, as shown in Figure 2. For example, If VDDIO is 5 V and VREFL is 0 V, AMUXBUS A, which is separated from VDDIO and the Reference Buffer by 100 kΩ of resisters, has a potential of 2.5 V that is smaller than the ADC reference voltage.
As in the earlier example, you can monitor VDDIO if it is higher than the ADC reference voltage.
Figure 2 ADC diagram for monitoring VDDIO with Reference Buffer and potential distribution
Note: This KBA applies to the following series:
- All TRAVEO™ T2G series