Hello ramesh,
CPU PADs of SD1 list is from datasheet:
Recommended design from MMC protocol:
1. Why CMD and Data0 lines has pulled-up any specific reasons related to processor ?
According to SD protocol, all signal lines should have external pull-up resistors.
2. Why other Data lines doesn't have Pull-ups?
During initialization, only CMD and DATA0 line work, other data lines(DATA1--DATA3) are not used. After initialization, SD interface can be configured as 4-line mode, and there exists internal pull-up resistor on every SD pad, software can sets driving capability for these pads via configuring different pull-up resistors.
3. By processor default it has Internal pull-up, so we didn't use external pull-ups?
Yes, right.
But According to above list shown, if you don't configure pads in software, SD1 pads have no pull-up resistors! so you had better refer to EVK to design your schematic.
Have a great day,
wediong sun
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