I'm using XINTF of TMS320C28346 with XCLKOUT = one-fourth XTIMCLK. With certain settings it can happen, that neither of the edges of XCLKOUT matches some of the "edges" of LEAD, ACTIVE or TRAIL periods. The data manual sprs516d.pdf, page 144 is ambiguous:
".... Strobes such as XRD, XWE0, XWE1, and zone chip-select (XZCS) change state in relationship
to the rising edge of XTIMCLK." ...............
".... For the case where XCLKOUT = one-half or one-fourth XTIMCLK, some strobes will change state either on the rising edge of XCLKOUT or the falling edge of XCLKOUT. ...."
In the following diagrams, where will happen "XZCS inactive high" and "XWE1 active low"?
Will it be aligned with the XCLKOUT edges shown in diagram 1?
Or will it be aligned with the edges of LEAD-, ACTIVE- and TRAIL-periods shown in diagram 2, that is aligned with rising edge of XTIMCLK?
Diagram 1
| XWRLEAD=3 |XWRACTIVE = 4+1 | XWRTRAIL=3|
300 MHz _ _ _ _ _ _ _ _ _ _ _ _ _ _
XTIMCLK _/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_
75 MHz _______ _______ _______ ____
XCLKOUT _____/ \_______/ \_______/ \_______/
_____ ____
XZCS_ \_______________________________________________/
_____________________ ____________________
XWE1_ \_______________/
Diagram 2
| XWRLEAD=3 |XWRACTIVE = 4+1 | XWRTRAIL=3|
300 MHz _ _ _ _ _ _ _ _ _ _ _ _ _ _
XTIMCLK _/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_
75 MHz _______ _______ _______ ____
XCLKOUT _____/ \_______/ \_______/ \_______/
_____ ________
XZCS_ \___________________________________________/
__________________ ____________________
XWE1_ \__________________/
Thanks,
Uwe Grossmann