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SPI problem - newbie - interfacing between two philips micros

hi all, i m interfacing my philips micro sdk lpc936(slave) wid philips arm micro sdk lpc2138(master).i m sending seven segment pattern thru master .the slave pin SS is connected to one port pin of master thet provides it logic high to select it as slave. do need to check the status of SS pin on slave side periodically between byte transfers? i m doing this wid polling on master side & interrupt driven on slave side.

i hav configured master spiclk as cclk/31 (58.5895/31.33 = 1.843MHz) & of slave as cclk/4 (7.373/4 = 1.843MHz) .do i need to consider anything else for spiclk.

however do we need to set spiclk on slave side also ,as it shud take that as input frm master only ? also do reply if there is anyother point that i m not taking into consideration i wud also appreciate directC source code for spi configuration of lpc936.

Reply to
abhay
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No. Why would you need to check it between byte transfers? Why would you need to check it at all? It's SPIF that you want to check, which indicates that the master has asserted SS, clocked in a byte, and negated SS. That's all you need to check.

A slave is clocked by the master.

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Dan Henry
Reply to
Dan Henry

but do we need to consider the clk limits for slave.coz the slave clks are not in exact multiples of spiclk from master.also how wud the interrupt be generated & how we gonna detect it.do u have some code regarding my problem?i wud be thankful to you in that case.

Reply to
abhay

Only the hardware limits of the slave device like max clock frequency.

That's got nothing to do with it. There is no such thing as a slave clock generator. The slave is clocked by the CLK of the SPI bus.

The interrupt is generated after 8 clock pulses from the master, when SS is asserted.

Meindert

Reply to
Meindert Sprang

I'm also facing the similar problem while interfacing the two micros where one is running at 50 MHz as master and the other at 10 MHz as slave. The limit mentioned for the SPI clock is 4.5MHz. I have clocked it at 2.5MHz and also at 1Mhz. There is no interrupt getting generated also the data is not transferred even in the polled way. What shall we keep in mind for having SPI for the commnication between these micros and I have to use mutiple of slave micros for one of my projects.

Reply to
manish.k.vashishtha

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