mass storage例程识别sdhc的卡很慢，原因找到，但是还没解决

只看该作者 · 2013-1-22 15:02

在调试mass storage例程识别各种卡的时候，发现识别sdhc的卡，很慢（接近十几秒）。利用bus hound抓取其枚举过程，发现普通卡和sdhc卡的区别在于
sdhc卡，主机发送了接近6-8秒的read命令。之前看资料说是只需要读取0扇区的512字节，为什么需要读取这么久，

如下是其中一部分数据；等到读完之后，即是TEST_UNIT_READY
  33.1  IN    00 00 00 00  00 00 00 00  ........       4.1ms       1.1.0
  33.1  IN    55 53 42 53  70 58 98 89  USBSpX..       1.9ms       2.1.0
  34 CMD 28 00 00 00  17 30 00 00  READ             67us       3.1.0
  33.2  OUT 55 53 42 43  70 58 98 89  USBCpX..       1.9ms       4.1.0
  33.1  IN    00 00 00 00  00 00 00 00  ........          11ms       5.1.0
  34 CMD 00 00 00 00  00 00       TEST UNIT READY 378us       6.1.0
  33.1  IN    55 53 42 53  70 58 98 89  USBSpX..       1.6ms       7.1.0
  34 IN    00 00 00 00  00 00 00 00  ........          45us       3.2.0
  34 CMD 28 00 00 00  17 38 00 00  READ             215us       8.1.0
  33.2  OUT 55 53 42 43  08 c0 63 89  USBC..c.       1.7ms       9.1.0
  33.1  IN    55 53 42 53  08 c0 63 89  USBS..c.       2.0ms       10.1.0
  34 ok                                                 41us       6.2.0
  33.2  OUT 55 53 42 43  70 58 98 89  USBCpX..       1.9ms       11.1.0
  33.1  IN    00 00 00 00  00 00 00 00  ........          11ms       12.1.0
  33.1  IN    55 53 42 53  70 58 98 89  USBSpX..       1.9ms       13.1.0
  34 IN    00 00 00 00  00 00 00 00  ........          10us       8.2.0
  34 CMD 28 00 00 00  17 40 00 00  READ             70us       14.1.0
  33.2  OUT 55 53 42 43  70 58 98 89  USBCpX..       1.9ms       15.1.0
  33.1  IN    00 00 00 00  00 00 00 00  ........          11ms       16.1.0
  33.1  IN    55 53 42 53  70 58 98 89  USBSpX..       1.9ms       17.1.0
  34 IN    00 00 00 00  00 00 00 00  ........          8us       14.2.0
  34 CMD 28 00 00 00  17 48 00 00  READ             63us       18.1.0
  33.2  OUT 55 53 42 43  70 58 98 89  USBCpX..       1.9ms       19.1.0
  33.1  IN    00 00 00 00  00 00 00 00  ........          11ms       20.1.0
  33.1  IN    55 53 42 53  70 58 98 89  USBSpX..       1.9ms       21.1.0
  34 IN    00 00 00 00  00 00 00 00  ........          7us       18.2.0
  34 CMD 28 00 00 00  17 50 00 00  READ             58us       22.1.0
  33.2  OUT 55 53 42 43  70 58 98 89  USBCpX..       1.9ms       23.1.0
  33.1  IN    00 00 00 00  00 00 00 00  ........          11ms       24.1.0
  33.1  IN    55 53 42 53  70 58 98 89  USBSpX..       1.9ms       25.1.0
  34 IN    00 00 00 00  00 00 00 00  ........          7us       22.2.0
  34 CMD 28 00 00 00  17 58 00 00  READ             54us       26.1.0

只看该作者 · 2013-1-23 10:10

怎么没人来看看，解决

只看该作者 · 2013-1-23 10:22

跟卡有关吧。这两天我们也遇到很奇怪的问题。有一张SD卡，在F1,F3,F4芯片和硬件上运行的好好的。完全的硬件基础上换成F2芯片就不行。不过对于F2,换张卡就行了。可以肯定硬件没问题。卡好像也没问题，毕竟其它芯片上OK,但就F2不行,而F2换张卡就又OK，原来的卡就不行。真是神了。楼主有其它卡的话，换换看看。。。？