MSP430FR2355: Digital Inputs 1.8V

QI Jepson

Part Number: MSP430FR2355

There is a 1.8V power supply and the serial port is connected to the MSP430. Whether it will cause the high level is not recognized.

over 6 years ago

0 QI Jepson over 6 years ago

Intellectual 320 points

MSP430FR2355 power supply 3V

0 Lixin Chen1 over 6 years ago in reply to QI Jepson

TI__Expert 7015 points

Hi, Jepson,
Could you help to clarify what the 1.8v power supply is for? Do you mean the MSP430FR2355 is power supplied by 3.3v, and it is connecting a device with UART interface for which the device is powered by 1.8v? If yes, it is recommended to add level shift on the UART signals between the MSP430FR2355 and the device.

Regards,
Lixin

0 QI Jepson over 6 years ago in reply to Lixin Chen1

Intellectual 320 points

yes.However, due to space constraints, customers cannot add level-shifting circuits, so there is a possibility that this part of the serial port may be garbled.

0 zrno soli over 6 years ago in reply to QI Jepson

Guru 34483 points

Is it possible to go down with FRAM VCC? To 2.0V for example.

0 Lixin Chen1 over 6 years ago in reply to zrno soli

TI__Expert 7015 points

Hi, Zrno,
It is possible if to power supply MSP430FR2355 with 2.0V. But the following points need to be considered:
(1) What is the maximum voltage the GPIO can tolerate on 1.8v device? If it is lower than 2.0v, the simple level shift circuit needs to be used, such as resistor divider. It is to divide the 2.0v high level voltage down to the 1.8v voltage which the 1.8v device UART Rx can tolerate.
(2) The UART Tx from 1.8v device will output 0~1.8v voltage to MSP430FR2355. It is no problem to connect it to MSP430FR2355 UART Rx pin directly because the Vit+max = 1.5v, and Vit-min = 0.5v (VCC=2.0v).

Regards,
Lixin

0 Lixin Chen1 over 6 years ago in reply to Lixin Chen1

TI__Expert 7015 points

Hi, Zrno,
If you have no any questions, I would like to close this thread. In case you come up with more questions, please reply on this thread or have another post.
Thanks,
Lixin

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MSP430FR2355: Digital Inputs 1.8V