c6748 SPI接多个从设备

user6310626

Intellectual 370 points

C6748 用的SPI1口，现需用SPI1_SCS[0]与SPI1_SCS[1]控制两个从设备。

我看了有关SPI的寄存器，没有相关的寄存器设置能做到下面功能。

比如：我写一个数据，我需要自动切换SPI1_SCS[0]与SPI1_SCS[1]，这一步如何能实现？

5 年多前

0 Nancy Wang 5 年多前

TI__Guru** 110395 points

可以通过改变SPIDAT1.CSNR来实现切换。
请参考starterware中spi代码。
processors.wiki.ti.com/.../StarterWare_SPI
Selecting CS pin to be driven, Format Register to be used and asserting CS pin is achieved using SPIDat1config().

0 user6310626 5 年多前回复 Nancy Wang

Intellectual 370 points

SPIBUF中的TXBUF RXBUF分别有多大啊？

0 Nancy Wang 5 年多前回复 user6310626

TI__Guru** 110395 points

具体请查看TRM 28.2.11.1 Character Length
Character length 2 to 16 bits.
Transmit data is written to SPIDAT1. The transmit data must be written right-justified irrespective of the character length. The SPI automatically sends out the data correctly based on the chosen data format.
The data received in SPIBUF is right-justified irrespective of the character length and is padded with 0s when character length is less than 16

0 user6310626 5 年多前回复 Nancy Wang

Intellectual 370 points

我指的是如图中所示的，TXBUF RXBUF的大小. 也就是比如RX收多少个字节，才会RXFULL

0 Nancy Wang 5 年多前回复 user6310626

TI__Guru** 110395 points

buffer大小是16bit.看一下手册图6-36.

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c6748 SPI接多个从设备