AM6442: IBIS model driver strength verification

Tool/software:

• I am performing SI analysis for an eMMC interface using the AM6442 processor and IS21EF16G-JCLI flash. In the AM6442 IBIS model (sprm810), I see the driver strength is only 40 Ω. Does this mean it only supports 40 Ω impedance? In my simulations, signals don’t meet the expected range without external termination, but they pass when I add a 22 Ω series termination. However, in the TMDS64EVM design, I don’t see any termination used on the eMMC interface. Can someone clarify why?