編者按：
AD7124作爲ADI研發的1款超高分辨率的Σ-Δ型ADC芯片，達到了驚人的24位分辨率，性能十分變態。
雖然硬件性能強悍，但是其軟件驅動卻十分複雜。不仔細研讀半個多月手冊，別想弄明白。坑不是一般的多。
如果不是擁有着很豐富的驅動調試經驗，很難能調出來的。
該款芯片讀多通道很雞肋，芯片只有1個data寄存器用來存放數據。這樣的話，讀多通道的時候，
就會很容易Miss掉其它的通道。[如果還不理解聯繫QQ：978924688]
下面介紹下給芯片的讀取技巧：
（1）從手冊看問題
If several channels are enabled, the ADC automatically sequences
through the enabled channels and performs a conversion on
each channel. When a conversion is started, DOUT/RDY goes
high and remains high until a valid conversion is available and CS
is low. As soon as the conversion is available, DOUT/RDY goes low.
The ADC then selects the next channel and begins a conversion.
The user can read the present conversion while the next conversion
is being performed. As soon as the next conversion is complete,
the data register is updated; therefore, the user has a limited
period in which to read the convers