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Altera_Forum
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8 years ago

Cyclone V sdcard pull-up

Hi All According to Cyclone® V Device Family Pin Connection Guidelines - SDMMC_CMD and SDMMC_D0 should have 10k pull-ups but there is no mention of pull-ups for SDMMC_D1, SDMMC_D2, SDMMC_D3. ...
Altera_Forum's avatar
Altera_Forum
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8 years ago

Hi, you are right it is recommended to have pull up on those data pins. I looked at the dev kit schematic and also the MMC jedec specification, the pull ups are recommended. Please note however that on D3, the SD simplified specification mention that there is an internal pull up (in SD card) that can be disabled by software.

https://members.sdcard.org/downloads/pls/simplified_specs/part1_410.pdf