I'm using a MPC5634. I want to send a 32-bit frame using SPI. But in configuration register i see, than i can send only 16 bit words.
Is it possible to send a 32 bit SPI frame on 55xx or 56xx?
Aren't two 16 bit SPI frames the same as a 32-bit one? All you need to do is to make sure the chip-select remains asserted for both of them.
I've read something recently on one of these forums where an SPI controller wouldn't allow this when it was "in charge" of the Chip Select lines. A simple fix is to program the SPI Chip Select pin as a GPIO and drive it in software around your calls to the SPI hardware that is sending the multiple frames.
This shouldn't be necessary as the Reference Manual (MPC5553/5554) states:
Chapter 20Deserial Serial Peripheral Interface (DSPI)
— Programmable serial frame size of 4 to 16 bits, expandable with software control— Continuously held chip select capability
I think you want:
Table 20-8. DSPIx_PUSHR Field Descriptions
Continuous peripheral chip select enable.Selects a continuous selection format. The bitis used in SPI master mode. The bit enables the selected PCS signals to remainasserted between transfers. See Section 220.127.116.11, “Continuous Selection Format,” formore information.0 Return peripheral chip select signals to their inactive state between transfers1 Keep peripheral chip select signals asserted between transfers
18.104.22.168 Continuous Selection Format
That should do what you want.
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