I have an existing design that uses the MSP430F2419. This chip has two USCI modules. These will accommodate 7 or 8 bit data words. I need to support a SPI device that uses variable data-bit lengths. So I need a chip with a USI module. I'd like to find a mostly pin-compatible part that offers a USI module. It would be OK to drop down from two USCI modules, to one USCI and one USI modules.
Can you offer part number suggestions?