最近在使用ads1278做采集,按照DS上的说法 SCLK要是CLK的 1 , 1/2 ,1/4倍 。但实际按照这样设置的时候发现读出的数据有问题。 按道理来说spi的sclk速度应该要高于采集时钟clk才可以的啊,实际测试也验证了这一点。但是为什么ds上说sclk要等与或者小于clk ?
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最近在使用ads1278做采集,按照DS上的说法 SCLK要是CLK的 1 , 1/2 ,1/4倍 。但实际按照这样设置的时候发现读出的数据有问题。 按道理来说spi的sclk速度应该要高于采集时钟clk才可以的啊,实际测试也验证了这一点。但是为什么ds上说sclk要等与或者小于clk ?
你应该是理解反了吧, 我看文字下面的时序图的
SCLK
The serial clock (SCLK) features a Schmitt-triggered
input and shifts out data on DOUT on the falling
edge. It also shifts in data on the falling edge on DIN
when this pin is being used for daisy-chaining. Even
though SCLK has hysteresis, it is recommended to
keep SCLK as clean as possible to prevent glitches
from accidentally shifting the data. When using
Frame-Sync format, SCLK must run continuously. If it
is shut down, the data readback will be corrupted.
The number of SCLKs within a frame period (FSYNC
clock) can be any power-of-2 ratio of CLK cycles (1,
1/2, 1/4, etc), as long as the number of cycles is
sufficient to shift the data output from all channels
within one frame.