I am designing Board with Vybrid VF6 and I have doubt about SDHC layout recommentaions appears in paragraph 126.96.36.199 SD Card interface requirements of ref. doc. VYBRIDHDUG_HW_UserGuide.
In this paragrap appears:
1. The clock trace should be longer than the longest trace in the Data /Command group (+5mils).
Is 5mils minimun distance or maximum ?
2. SD card interface layout requirements are very similar to those for the DDR one (see Section 3.5,
“DDR routing rules”).
But in this section appears DDR3 recommnedations?
I need to kown routing recomentadion to SDHC.
Can somebody help me?
Thank you in advance.
Solved! Go to Solution.
yes, reference design uses DRAM memory type DDR3 (DDR is imprecise expression).
SDHC runs up to 50MHz.
- try to make lines short
- match all lines length.
- Add 5 mils to clk.
- try to keep lines on one layer.
- Ensure correct return path (continuous ground under lines)
- consider ESD protection if SD card is accessible to users.