2.4 SPI Communication

Similar to the UART mode, the MSP-BSL supports the SPI protocol starting from firmware version 3.0. All data send to the virtual COM port is output through the SOMI, SIMO, CLK, and STE pins (see Section 4.2). A state machine on the MSP-BSL makes the communication appear as transparent UART to the outside.

To start SPI BSL communication, perform the following steps, depending on the device family.

For the MSP430 family:

1. The SPI BSL is not supported for MSP430 BSL

For the MSP432P4xx family:

1. The SPI BSL operates with the default configuration of:
   1. Data is changed on first clock edge and captured on the following edge (CKPH = 0).
   2. The clock is high when inactive (CKPL = 1).
   3. The slave transmit enable is active low.
   4. Uses 8-bit serial data character format.
2. The host starts the programming with 125000, 250000, 500000, or 1000000 standard bit rate.

For the MSP432E4 family:

1. The host triggers the MSP-BSL Rocket with 125008, 250008, 500008, or 1000008 bit rate.
2. The SPI BSL operates with the default configuration of:
   1. Data is changed on first clock edge and captured on the following edge (CKPH = 0).
   2. The clock is low when inactive (CKPL = 0).
   3. The slave transmit enable is active low.
   4. Uses 8-bit serial data character format.
3. Host starts the programming with 125000, 250000, 500000, or 1000000 standard bit rate.