SPRZ342O January 2011 – April 2021 TMS320F28062 , TMS320F28062-Q1 , TMS320F28062F , TMS320F28062F-Q1 , TMS320F28063 , TMS320F28064 , TMS320F28065 , TMS320F28066 , TMS320F28066-Q1 , TMS320F28067 , TMS320F28067-Q1 , TMS320F28068F , TMS320F28068M , TMS320F28069 , TMS320F28069-Q1 , TMS320F28069F , TMS320F28069F-Q1 , TMS320F28069M , TMS320F28069M-Q1
eQEP: Missed First Index Event
0, A, B
If the first index event edge at the QEPI input occurs at any time from one system clock cycle before the corresponding QEPA/QEPB edge to two system clock cycles after the corresponding QEPA/QEP edge, then the eQEP module may miss this index event. This condition can result in the following behavior:
Reliable operation is achieved by delaying the index signal such that the QEPI event edge occurs at least two system clock cycles after the corresponding QEPA/QEPB signal edge. For cases where the encoder may impart a negative delay (td) to the QEPI signal with respect to the corresponding QEPA/QEPB signal (that is, QEPI edge occurs before the corresponding QEPA/QEPB edge), the QEPI signal should be delayed by an amount greater than "td + 2*SYSCLKOUT".