ads7953无法切换通道，读出的数据时钟是通道0的数据

Fig 52 of the ADS7953 datasheet describes the steps involved in programming the device for Auto-1 Channel-sequencing mode.

Let us assume that the customer is interested in configuring the device to capture data from Channels 1,3 and 5, in Range 2 and with GPIO0 as output high

Here is the sequence of commands to send over the SDO to configure the device:

>> wr 0x4200 // Device resets all registers in the next CS frame to the reset states (it also resets itself).

>> wr 0x4001 // Configure GPIO0 as a general purpose output

>> wr 0x8000 // Program Register for Auto-1 Frame 1

>> wr 0x002A // Program Register for Auto-1 Frame 2, to select channels Ch1,Ch3 and Ch5

>> wr 0x2C40 // Enable Auto-1 Mode, counter set to lower programmed channel (Ch1), Select Range 2 operation

>> wr 0x2841 // Stay in Auto-1 Mode, enable increment counter, Range 2 operation and GPIO set as output high

The device is now configured and these setting can be retained by driving SDI low. The channel selection will cycle through the 3 channels with each subsequent frame.