The statement on Gate3.Chan[j].TimerMode in the User's Manual (page 473) is what exactly confused me:
(1) " All 3 elements are unsigned 32-bit integer values, in units of 1/4096 of a count of the encoder. That is, they have 20 bits of full-count information, and 12 bits of fractional-count information."
(2) "If saved setup element Gate3.Chan[j].TimerMode is set to its default value of 0, “hardware 1/T” count extension is enabled for the channel to calculate an estimated fractional-count value every SCLK cycle. The IC can then compare the combined whole-count and fractional-count value against the values in the compare registers, which have 24 bits of whole-count data and 8 bits of fractional data."
Which fractional-counts is used then: 12 bits or 8 bits?
Initially, I thought 12bits fractional-counts is for sinusoidal encoder, 8bits is for quadrature encoder. Since a sinusoidal encoder is used for my case (Gate3.Chan[j].AtanEna=1), I thought the setting of TimerMode does not matter.