The Measured Current Is Smaller Than Set in the CapSense® User Modules and IDACL_D/IDACR_D Registers – KBA92751

Version: **

 

Question: The measured current is smaller than the current set in the CapSense® User Modules and IDACL_D/IDACR_D registers on the CY8C21x45, CY8C22x45, and CY8C28xxx devices. What is the reason for this and what is the workaround?

 

Answer:

The PSoC® 1 iDACs are not trimmed by default. To get correct iDAC values, the iDACs should be trimmed. Use the following command to trim the iDACs:

DAC_CR1 |= 0x10;

The command should be executed before the CapSense_Start API. The trimming operates correctly because the CapSense User Modules do not change the IDAC_TRIM bitfields of the IDAC_CR1 register.