- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi Cypress Team,
Would you kindly answer why the raw count value(CapSense_bistRawcount) in bist function api CapSense_GetSensorCapacitance is not equal to the raw count in CapSense_dsRam.snsList.button0[0].raw[0]
I configure capsense component just same to the settings in CapSense_GetSensorCapacitance. Then when I debug the project, I got 0x374 of the CapSense_bistRawcount, and CapSense_dsRam.snsList.button0[0].raw[0] is 0x8f.
I attached my project
Thanks very much
Sophie
Solved! Go to Solution.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
Hi user_264721,
The difference is coming from the Vref used for both these measurements. If you are using 145 kit for this test, it uses 5 V VDDA, therefore Vref chosen for normal scanning is 2.74 V. But BIST uses Vref as 1.2 V (~2.25 times lower), that is why you are seeing this difference. If you make Vref as 1.2 V for normal operation (not required / not recommended), you should be seeing the same rawcounts.
Also from your project, button0 is a mutual capacitance button. Rawcounts of CSX button translates to Cm and not Cp. BIST performs CP measurement only. You should be probably looking at Button 1 or Button 2 where you have configured each tx or rx segment as CSD buttons. From your description, you should be looking at BUTTON 1. Please check this.
I ran your code with Vref set as 1.2 V for normal scan (using expression view - not recommended/ needed). I compared the rawcounts of BUTTON1 (RX segment connected as CSD button). The rawcounts obtained from the normal scan and BIST scan were same.
Regards,
Bragadeesh
Bragadeesh