The maximum clock frequency that can be used with the internal oscillator is 16 MHz. However, it's recommended to use a clock frequency of 12 MHz or less to ensure reliable operation.
To configure the MSP430F1121AIDGV for low-power operation, you can use the Power Management Module (PMM) to select the lowest possible clock frequency, disable unused peripherals, and use the Low Power Mode 3 (LPM3) or Low Power Mode 4 (LPM4) modes. You can also use the Dynamic Voltage Scaling (DVS) feature to reduce the voltage supply to the core and peripherals.
The maximum current that can be sourced or sunk by the GPIO pins is 4 mA. However, it's recommended to limit the current to 2 mA or less to ensure reliable operation and prevent damage to the device.
To use the USCI module for UART communication, you need to configure the USCI module as a UART, select the correct baud rate, and enable the transmitter and receiver. You can use the USCI_A or USCI_B module for UART communication, depending on the specific requirements of your application.
The JTAG pins on the MSP430F1121AIDGV are used for debugging and programming the device using the Joint Test Action Group (JTAG) interface. The JTAG interface allows you to access the device's memory and registers, and perform debugging and testing operations.