SPI.beginTransaction() does not work - help

[litian85734]

Dear All sirs: I use STM32F401 SPI HW mode drive the TFT LCD, but the speed is very low even worse than soft SPI mode, I try to use SPI.beginTransaction(SPISettings(XXXX, MSBFIRST, SPI_MODE0)) to change the SPI speed, but seems no use, Anybody meet same issue?

Thanks

[fpistm]

Hi @litian85734 could you be more precise (setup, LCD, core version, board, ...) and share your sketch.

[stas2z]

Ive played with st7735 spi lcd last week, using f401cc blackpill, and can say SPI.beginTransaction works fine, ive made a test using 10kb bitmap drawing in a loop which changed spi clock, drawing speed changed as expected. Also ive tested software spi bitbanging in compare with hw spi and it was much slower. So probably your lib have an issue with hw spi implementation

[BennehBoy]

+1 There a re a lot of broken SPI implementations out their in user library land.

On Fri, Oct 18, 2019 at 7:32 PM stas2z notifications@github.com wrote:

Ive played with st7735 spi lcd last week, using f401cc blackpill, and can say SPI.beginTransaction works fine, ive made a test using 10kb bitmap drawing in a loop which changed spi clock, drawing speed changed as expected. Also ive tested software spi bitbanging in compare with hw spi and it was much slower. So probably your lib have an issue with hw spi implementation

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[fpistm]

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