SLAA558A November 2012 – October 2018 MSP430F5212 , MSP430F5214 , MSP430F5217 , MSP430F5219 , MSP430F5222 , MSP430F5224 , MSP430F5229 , MSP430F5252 , MSP430F5253 , MSP430F5254 , MSP430F5255 , MSP430F5256 , MSP430F5257 , MSP430F5258 , MSP430F5259
The MSP430F522x and MSP430F521x devices support a split supply I/O system that is essential in systems in which the MCU is required to interface with external devices (such as sensors or other processors) that operate at different voltage level compared to the MCU device supply. Additionally, the split supply input voltage range of the F522x and F521x devices starts as low as 1.62 V (see the device data sheet specifications), and this allows for nominal 1.8-V I/O interface without the need for external level translation. This application report describes the various design considerations to keep in mind while designing the F522x and F521x devices in an application.
The application report discusses the new features of F522x and F521x devices, which mainly include the split-supply I/O system and the various digital functions supplied from the split-supply I/O rail.
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For split-supply I/O systems, the split supplies are connected to the VCC (DVCC and AVCC) and DVIO pins. Supply voltage at DVCC and AVCC pins (VCC) is used to provide device power, and the supply voltage at the DVIO pin (VIO) is used to supply the I/O rail of the "DVIO supplied I/O pins". The recommended VCC supply voltage ranges from 1.8 V to 3.6 V (see note A on Figure 1) and, therefore, these devices do not operate at nominal 1.8 V (that is, 1.8 V ± 10%) supply voltage level. The VIO supply voltage ranges from 1.62 V to VCC and is useful in applications that interface with nominal 1.8-V I/O interface (that is, 1.8 V ± 10%).