Spi Data

Support
1

Hello everyone,
I’m allowing myself to create this post because I’m new to this field and need a bit of help. I have a Saleae logic analyzer, the 100Ms model, and using the Saleae software, I connected it to the SPI bus (MISO/MOSI/CLK and CS) on a Silicon Labs IC, the SI4463.

My problem is that I can’t see the HEX values that I know are being sent through the SPI bus. The HEX data are 98 C7 36 01, CD 03 D6 61, and DA D7 78 71. All three blocks of data are in different files attached here. The data are in these files, but I don’t understand why the HEX values don’t follow one another, for example, why DA D7 78 71 isn’t grouped in the same block. Instead, they’re all scattered among other data, and I can’t figure out the logic.

I’d like to know if anyone has a bit of time to take a look at these files and tell me if they understand the logic behind how the data are scattered. Or at least let me know if the CLK is configured correctly or if I’m making some mistake in the settings. Thank you very much in advance!

Wang .
Second Sniff CD 03 D6 61.sal (12.5 KB)
CD 03 D6 61.sal (11.6 KB)
98 C7 36 01.sal (11.0 KB)
Second Sniff 98 C7 36 01.sal (11.0 KB)
Second Sniff DA D7 78 71.sal (11.1 KB)
DA D7 78 71.sal (12.2 KB)

2

First off your sample rate (40 MS/s) is too low. I’d suggest at least 100MS/s. Otherwise your configuration seems to be correct.

It’s not clear that the SPI clock rate is correct. The data sheet suggests the maximum clock rate is 10MHz, but the actual rate seems to be 12MHz.

To help determine what might be going wrong it would help if you told us where in the collected data the data of interest is. You could do that by putting timing markers in your data files so it is easy for us to find your problematic data.

1 Like