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SPI works MOSI - does nothing MISO! HELP! | Cypress Semiconductor

SPI works MOSI - does nothing MISO! HELP!

Summary: 2 Replies, Latest post by rxdesign on 02 Mar 2009 11:38 AM PST
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rxdesign's picture
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I have a CY6936 connected to an Atmel AVR device... I've confirmed the SCK and MOSI is working and that the 6936 is getting the data as I've changed the Xout to 750K from it's default of 12M. But when I try to read a register the MISO never changes - it remains at a high. I can see 2 streams of SCK - one telling it to read register 3 (for example) and one there to clock it in... The pin on the micro is programmed as an input and it has a weak pull-up... nothing ever on MISO.

HELP anyone?

Stub for 4858768's picture
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Hi rxdesign,

Sorry, we do not support the use of our devices with non-Cypress MCUs.

rxdesign's picture
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Originally posted by: rxdesign

I have a CY6936 connected to an Atmel AVR device... I've confirmed the SCK and MOSI is ...........................................telling it to read register 3 (for example) and one there to clock it in... The pin on the micro is programmed as an input and it has a weak pull-up... nothing ever on MISO.

HELP anyone?

I found the answer: the nSS line has to be taken back high and then low again. I.e. one cannot take the nSS line low, do a write and then do a read and then take the nSS line high again. Don't see this anywhere in the manual, possibly I missed it in my 100 or so perusals.... discovered it by playing with it.

As for the response given by Cypress that they don't support THEIR devices when connected to other MCU's... read my response under my other RF Wireless forum question about using it as an RS232 device. [my questions: both of them, have NOTHING to do with the MCU - they're regarding the Cypress device! ]

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