SWRU543B January 2019 – June 2025 CC3230S , CC3230SF , CC3235MODS , CC3235MODSF , CC3235S , CC3235SF
Continuous transfers are manually allowed, by keeping the SPIEN signal active for successive SPI words. Several sequences (configuration – enable – disable of the channel) can be run without deactivating the SPIEN line.
The keep SPIEN active mode is authorized when:
When the channel is enabled, the SPIEN signal is activated with the programmed polarity. The start of the transfer depends on the status of the transmitter register and the status of the receiver register.
The status of the serialization completion of each SPI word is given by the EOT bit of the SPI_CHSTAT register. The EOT bit is set when received data is loaded from the shift register to the receiver register.
A change in the configuration parameters is directly propagated on the SPI. If the SPIEN signal is activated, the user must ensure that the configuration is changed only between SPI words, to avoid corrupting the current transfer. SPIEN polarity, the SPICLK phase, and SPICLK polarity must not be modified when the SPIEN signal is activated. The channel can be disabled and enabled while the SPIEN signal is activated.
At the end of the last SPI word, the channel must be deactivated (MCSPI_CHCTRL[EN] set to 0) and the SPIEN can be forced to its inactive state (MCSPI_CHCONF[FORCE]).
Figure 8-6 shows successive transfers with SPIEN kept active low, with a different configuration for each SPI word in single data pin interface mode and two data pins interface mode. The arrows indicate when the channel is disabled before a change in the configuration parameters, and then enabled again.
Figure 8-6 Contiguous Transfers With SPIEN Kept Active (Two Data Pins Interface Mode)