Can you implement a 3-wire SPI in a PSOC1?

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Anonymous
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I have to interface a CY8C29466 to an Analog Devices ADRF6520. This device uses a 3-wire interface rather than the usual 4-wire. My question is whether it is possible to implement a 3-wire SPI on this device without using an external tri-state device.

The user module datasheet for the SPI master doesn't clearly say that you can do this, but in PSOC Designer I can connect MOSI and MISO to the same row output line. This implies that a 3-wire interface is possible, otherwise this ought to be an illegal connection. But I'm not convinced this is all correct, since I do not see how to tri-state the MOSI output when doing a read operation.

Has anyone had success with this? Thanks for your help.

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SampathS_11
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Hello Simon,

Though the PSoC Designer allows you to connect MOSI and MISO in the same row output line, we cannot do it for SPI, since we would not be able to read from other devices.

Also, it is not possible to tri-state MOSI internal to PSoC1, and also do it in between bits, as required by the ADRF6520.

Sampath

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SampathS_11
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250 sign-ins 250 solutions authored 5 questions asked

Hello Simon,

Though the PSoC Designer allows you to connect MOSI and MISO in the same row output line, we cannot do it for SPI, since we would not be able to read from other devices.

Also, it is not possible to tri-state MOSI internal to PSoC1, and also do it in between bits, as required by the ADRF6520.

Sampath

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