SD card SPI mode initialization sequence

In order to initialize the SD card into SPI mode, we need to use three commands: CMD0, ACMD41, CMD55 (CMD55 should be sent before using ACMD commands, CMD55 plays a role in switching to ACMD commands). 
Why not use CMD1 after using CMD0? CMD1 is the command used by MMC cards. Although this article does not want to discuss the issue of MMC cards, I still want to say: In order to achieve compatibility, after powering on or sending CMD0, you should first send CMD55+ACMD41 to confirm whether there is a response. If there is a response, it is an SD card. If the response timeout occurs, it may be an MMC card, and then send CMD1 to confirm. 
The correct response content should be:
    CMD0——0x01 (SD card is in-idle-state)
    CMD55——0x01 (SD card is in-idle-state)
    ACMD41——0x00 (SD card jumps out of in-idle-state, completes initialization and prepares to receive the next instruction)
    What I want to say here is that if the final response content is still 0x01, you can send CMD55+ACMD41 in a loop until the response content is 0x00. 
Among all the instructions, only CMD0 is special. Before sending it to the SD card, 74+ clocks need to be sent to the SD card. So why 74 CLKs? Because at the beginning of power-on, the voltage rise process is calculated by the SD card organization to reach the normal working voltage of the SD card in about 64 CLK cycles. They call this Supply ramp up time. The subsequent 10 CLKs are for synchronization with the SD card. After that, the operation of CMD0 is started. If you strictly follow this operation, there will be no problem. 
Regarding the SPI bus of the SD card, when reading data, the SPI of the SD card is input latched on the rising edge of CLK, and the output data is also on the rising edge. 
The process of writing a CMD or ACMD instruction to the SD card is as follows:
first, make CS low and enable the SD card; secondly, write the instruction to the Din of the SD card; after writing the instruction, add 8 filling clocks to complete the internal operation of the SD card; then receive the response on the Dout of the SD card; after receiving the response, make CS low and add 8 filling clocks. 
When there is no data written to the Din of the SD card, Din should be kept high.