How can I make a 16bit SPI master with st7lite19b for max3100 communicaiton

btjung · ‎2006-10-29

Posted on October 30, 2006 at 06:33

btjung · ‎2006-10-29

Posted on October 29, 2006 at 22:39

Hello,

ST7LITE19B can be used for 8bit SPI master or slave.

I'm trying to connect the MAX3100(SPI-UART) with ST7LITE19B.

ST7 is the master, and max3100 is the slave.

Max3100 requires 16bit data stream, but I cannot make a 16bit data stream.

Basically, ST7 provides 8bit data stream.

Does anybody has a code for SPI-UART communicaito?

Or let me hear some advice.

[ This message was edited by: btjung on 30-10-2006 03:10 ]

wolfgang2399 · ‎2006-10-29

Posted on October 30, 2006 at 06:33

Hi,

as the SPI uses asynchronous data transmission, there should be no problem, when you split the 16bit-word into two 8bit-words. Hold the \CS-pin of the MAX3100 down until the second byte has been transmitted. In the same way you will receive two 8bit-words and must reassemble them to your 16bit-word.

- First pull down the \CS-pin of the MAX3100.

- Start the 1st 8bit-transmission by writing the 1st byte to the SPIDR.

- When this transmission has been completed, the flag SPICSR.SPIF will occur.

- Fetch the received 1st byte.

- Start the 2nd transmission by writing the 2nd byte to the SPIDR.

- With the next SPICSR.SPIF you fetch the received 2nd byte.

- Pull high the \CS-pin of the MAX3100.

- Ready.

Regards WoRo