If I have a single ADCINC, I can move it around any place it on any analog column, and I can see there are Analog and Digital blocks free to be used, but why I keep getting "unable to place ADCINC user module because of resource allocation" when I try to place a 2nd ADCINC?
In most PSoC 1 devices, there is only one decimator resource which is used by ADCINC user module though the decimator is not appeared in the chip editor window.
ICLKS0 bit in DEC_CR0 register along with bits ICLKS3, ICLKS2, and ICLKS1 in the DEC_CR1 register determines the Incremental/SSADC Gate Source, with the configuration of the above bits, one of the digital block is selected to drive the decimator, so once a ADCINC is placed, a digital block which will drive the decimator is fixed, while place the second ADCINC, PSoC Designer will try to use another digital block to drive the decimator, which is undoable. Then PSoC Designer will give error message as "The resource assignments are not possible."
The CY8C28xxx family of PSoC offers 4 decimators. PSoC 3 and PSoC 5 have one dedicated hardware decimator. More decimators can be built in PSoC 3 and PSoC 5 using the Universal Digital Blocks (UDB)