在SD卡协议里面有这么一段,这个索引应该是0~63才对,在是在2440的SDI Command Control Register (SDICmdCon)怎么会这样设置呢?
A command always starts with a start bit (always 0), followed by the bit indicating the direction of
transmission (host = 1). The next 6 bits indicate the index of the command, this value being interpreted
as a binary coded number (between 0 and 63). Some commands need an argument (e.g. an address),
which is coded by 32 bits. A value denoted by ‘x’ in the table above indicates this variable is dependent
on the command. All commands are protected by a CRC (see Chapter 4.5 for the definition of CRC7).
Every command codeword is terminated by the end bit (always 1). All commands and their arguments
are listed in Table 4-18-Table 4-27.