MSP430FR5994: GPIO

Hello,

Gaosheng Liu said:

When I try to supply other peripherals by GPIOs(e.g. p6.0) on the msp430fr5994 launchpad, It can work. And the voltage value is around 3 V.

By "other peripherals", do you mean external devices? If so, you can power those devices if they don't draw much current (uA range), but a much better approach would be to power them directly from the same source as VCC and use the GPIO to enable/disable those devices. Typically, the GPIOs will operate on the same logic levels as the VCC voltage.

To learn more about the expected voltages on the GPIO pins, check out Section 8.12.5.2 Digital Outputs in the datasheet. Also, the plots in Section 8.12.5.3 Typical Characteristics illustrate how the output voltage drops as the output current increases (mA range).

In general, I would avoid trying to power other devices in your design through GPIOs. A common approach for controlling LEDs is to power them from VCC and control the ground side rather than power side to minimize power dissipation through the device.