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JESD84-A44
/ f6 `+ b; k" X- W( FDAT0-DAT7: These are bidirectional data channels. The DAT signals operate in push-pull mode. Only
; O9 H+ t: e1 i% x5 P' ~the card or the host is driving these signals at a time. By default, after power up or reset, only DAT0 is
" S' ~3 \. S6 M$ Z7 ~0 @% NJEDEC Standard No. 84-A44 Page 15 used for data transfer. A wider data bus can be configured for data transfer, using either DAT0-DAT3 or DAT0-DAT7, by the MultiMediaCard controller. The MultiMediaCard includes internal pull-ups for data lines DAT1-DAT7. Immediately after entering the 4-bit mode, the card disconnects the internal pull ups of lines DAT1, DAT2, and DAT3. Correspondingly, immediately after entering to the 8-bit mode the card disconnects the internal pull-ups of lines DAT1–DAT7.6 {- ?- E" Z# [
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发表于 2015-5-18 16:51
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支持！
反对！
发表于 2015-5-26 11:41