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microcontroller in SPI Slave mode when clock is continous and no SSEL

Please can i have your help?

I'm confused about the following situation:

A transceiver is connected in SPI mode to a microcontroller(LPC12xx). The transceiver outputs a continous clock ,and it does not drive any SSEL line to enable the SPI section of the microcontroller. The microcontroller should decide when to start a data transmission,but just enabling its SPI module it goes in Busy condition and i have found no way to change it. Polling the BSY flag goes to a never ending loop,just as the uC is still sending out something,or receiving and it is always busy.

How is the right way to deal with similar situations?

Many thanks for help or hints or links Diego

Reply to
blisca
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If your transceiver outputs a continuous clock, and has no SSEL, then how does it expect the receiving device to frame the data?

--
Rob Gaddi, Highland Technology -- www.highlandtechnology.com 
Email address domain is currently out of order.  See above to fix.
Reply to
Rob Gaddi

"Rob Gaddi" ha scritto nel messaggio news: snipped-for-privacy@rg.highlandtechnology.com...

Thanks for your answer Mine is..I dont'know... the transceiver is

formatting link
if you take a look at page 46 Figure 60 you can see how microcontroller and transceiver are connecter.None of lower output signals SWD or SREAD acts as SSEL.

At least i could use those signals to write into control registers,to enable TX mode only when i need it,but i don't think that i could have a known number of clock pulses in this way.

Thanks for your attention Diego

Reply to
blisca

You mean this figure 60, the one that states: Figure 60. ADF7021-N (UART Mode) to Asynchronous Microcontroller Interface

This is NOT using the SPI interface for this mode of operation.

The paragraph heading should have told you something: UART Mode

Please re-read these paragraphs and form your question from there.

Its figure 61 that uses SPI.

hamilton

Reply to
hamilton

Thank you , i realized that the datasheet in my PC is not the same as the one that i linked. Is Figure 61.

Reply to
blisca

To your original question:

The payload interface (TxRxCLK and TxRxDATA) transfers just a raw bit stream with no framing provided, see figures 8 and 9 in the linked data sheet. It is up to you to decode the bit porridge. A suggested framing is in figure 54 of the data sheet. The raw bit stream is not very well suited to a SPI interface, though it is so named by AD.

You might be better off using the UART mode with an UART interface on the host processor.

--

Tauno Voipio
Reply to
Tauno Voipio

Thank you too,Tauno i did something working on SPI,but i 'm not able to master it completely, by now i'm on a trivial software handling of that communication,using a GPIO edge interrupt and a pulse clock counter and it works correctly. UART mode is not allowed for the modulation that was decided by the RF pals

Thanks again to you all

Reply to
blisca

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