差别

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后一修订版 		前一修订版
sd_card [2017/03/26 22:04]
gongyu 创建 		sd_card [2020/01/18 22:18] (当前版本)
gongyu
行 9: 行 9:
 {{ ::​sd_modes.gif |}} {{ ::​sd_modes.gif |}}
  
-====== ​SPI mode ======+#### SPI模式
  
 In SPI mode, the DI/DO lines are unidirectional. That means: In SPI mode, the DI/DO lines are unidirectional. That means:
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 {{ ::​sd_fpgaonebit.gif |}} {{ ::​sd_fpgaonebit.gif |}}
  
-====== ​协议 ​======+#### 协议
  
 SD cards work with a command/​response scheme. For example, command "​17"​ allows reading one sector (512 bytes) of the card memory. All communication is synchronous to a clock provided by the host (FPGA in our case). The clock should run below 400KHz at startup and can go faster after some card initialization. SD cards work with a command/​response scheme. For example, command "​17"​ allows reading one sector (512 bytes) of the card memory. All communication is synchronous to a clock provided by the host (FPGA in our case). The clock should run below 400KHz at startup and can go faster after some card initialization.
行 39: 行 39:
  
 <code verilog> <code verilog>
- 
 // we use the Xylo-E FX2 FIFO2 as data source for "​commanding"​ an SD card // we use the Xylo-E FX2 FIFO2 as data source for "​commanding"​ an SD card
 // the SD card is used in one-bit SD mode // the SD card is used in one-bit SD mode
行 67: 行 66:
   * CMD8 "​SEND_IF_COND",​ response expected   * CMD8 "​SEND_IF_COND",​ response expected
  
-Here's a session recorded using Xylo-E'​s demo software: +#### 相关资源 
- +  ​* ​Seabright技术公司的[[http://​wiki.seabright.co.nz/​wiki/​SdCardProtocol.html|SD卡的协议]] 
-❌SD.exe +  ​* ​Wikipedia上[[http://​en.wikipedia.org/​wiki/​Secure_Digital|关于SD卡的介绍]]. 
-USB driver opened +  ​* ​SD联盟的最新[[https://​members.sdcard.org/​downloads/​pls/​simplified_specs/​part1_410.pdf|简化SD规范]] ​
-CMD0 400000000095 +
-CMD8 48000001AA87... OK +
-CMD55 770000000065... OK +
-CMD41 694018000019... OK +
-CMD55 770000000065... OK +
-CMD41 694018000019... OK +
-SDHC/SDXC (high capacity) card +
-CMD2 42000000004D... OK +
-ASTC  3.4 +
-CMD3 430000000021... OK +
-RCA=0100 +
-CMD7 4700010000DD... OK +
-CMD13 4D0001000053... OK +
-CMD17 510000000055... OK +
-FAT32 detected +
-Reading 1 sector(s) starting at 8192 +
-CMD17 5100002000B1... OK +
-Directory / +
- +
- +
-After some initialization,​ the card accepts CMD17 "​READ_SINGLE_BLOCK"​ so that files can be read from the card. +
- +
-====== ​相关资源 ​====== +
- +
-Seabright技术公司的[[http://​wiki.seabright.co.nz/​wiki/​SdCardProtocol.html|SD卡的协议]] +
-Wikipedia上[[http://​en.wikipedia.org/​wiki/​Secure_Digital|关于SD卡的介绍]]. +
-SD联盟的最新[[https://​members.sdcard.org/​downloads/​pls/​simplified_specs/​part1_410.pdf|简化SD规范]] ​+