MPC8379E PowerQUICC II Pro Processor Hardware Specifications, Rev. 8
Freescale Semiconductor
47
tCLK_DELAY + tIH – tSFSKHOX < tSFSCKL+ tDATA_DELAY
Eqn. 5
This means that clock can be delayed versus data up to 15 ns (external delay line) in ideal case of
tSFSCLKL =20 ns:
tCLK_DELAY + 5 – 0 < 20 + tDATA_DELAY
tCLK_DELAY < 15 + tDATA_DELAY
11.2.1.3
Full-Speed Write Combined Formula
The following equation is the combined formula to calculate the allowed skew range between the
SD_CLK and SD_DAT/CMD signals on the PCB.
tCLK_DELAY + tIH – tSFSKHOX < tSFSCKL + tDATA_DELAY < tSFSCK+ tCLK_DELAY – tISU – tSFSKHOV
Eqn. 6
11.2.2
Full-Speed Input Path (Read)
This figure provides the data and command input timing diagram.
Figure 28. Full Speed Input Path
11.2.2.1
Full-Speed Read Meeting Setup (Maximum Delay)
The following equations show how to calculate the allowed combined propagation delay range of the
SD_CLK and SD_DAT/CMD signals on the PCB.
tCLK_DELAY + tDATA_DELAY + tODLY + tSFSIVKH < tSFSCK
Eqn. 7
tCLK_DELAY + tDATA_DELAY < tSFSCK – tODLY – tSFSIVKH – tINT_CLK_DLY
Eqn. 8
tCLK_DELAY
Output from the
SD CLK at
the card pin
SD card pins
tSFSIVKH
tSFSIXKH
Driving
edge
Sampling
edge
tOH
tDATA_DELAY
tODLY
tSFSCK (clock cycle)
(MPC8379E input hold)
SD CLK at the
MPC8379E pin
Input at the
MPC8379E pins