ads7953采用手动模式,可以正常读出通道0的数据,但无法切换到其他通道,例如RW_ADS7953(0x18,0xC0);返回的值仍为通道0的数据,请问是什么原因导致的?spi的clk使用过1MHZ~8MHZ,都是这个情况
Star Xu:
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.