标题: EMMC 的8位数据线是否可以颠倒顺序？ [打印本页] 作者: yujingfa 时间: 2015-5-18 16:51 标题: EMMC 的8位数据线是否可以颠倒顺序？ DDR的数据线是可以相互颠倒顺序的。现在不知道EMMC 的8位数据线是否可以颠倒顺序。能颠倒顺序就好！请大侠指导一下！并帮忙解释。 作者: 超級狗 时间: 2015-5-26 11:41
JESD84-A44
DAT0-DAT7: These are bidirectional data channels. The DAT signals operate in push-pull mode. Only
the card or the host is driving these signals at a time. By default, after power up or reset, only DAT0 is
JEDEC 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.
