Full duplex SPI MODE 3 CS line pulls down at same time of CLK
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- Posts: 11
- Joined: Thu Jul 26, 2018 3:20 pm
Full duplex SPI MODE 3 CS line pulls down at same time of CLK
When capture signal on my digital analyzer in mode 3, the digital analyzer always complains "CLK idle error". If I set my digital analyzer to mode 0, it can decode the signal. I found the CS pulls down at same time of CLK. Should the CS pull down before CLK?
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- DECODE at mode 3.png (30.72 KiB) Viewed 4551 times
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- cs and clock at same time.png (37.64 KiB) Viewed 4551 times
Re: Full duplex SPI MODE 3 CS line pulls down at same time of CLK
Generally CS should be always toggled before CLK signal. There is a hardware bug where setting cs_ena_pretrans does not have any effect in full duplex.
You can control CS line as GPIO (set it low before SPI transmission, set it high after transmission).
You can control CS line as GPIO (set it low before SPI transmission, set it high after transmission).
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- Posts: 11
- Joined: Thu Jul 26, 2018 3:20 pm
Re: Full duplex SPI MODE 3 CS line pulls down at same time of CLK
Thank you very much for your reply.
So what is the work around for now if I want to use DMA ? define a GPIO and set it in pre call function and reset in post call function?
So what is the work around for now if I want to use DMA ? define a GPIO and set it in pre call function and reset in post call function?
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