ad7793的调试记录

1、如果是单片机控制一个ad7793，那么使用检测drdy引脚低电平来检测adc是否转换完成。

2、如果是单片机控制多个ad7793，那么不能使用检测drdy引脚低电平来检测adc是否转换完成，因为此时DRDY引脚是高阻态，无法检测低电平。
英文如下：
Yes, you can use this on a shared SPI bus. Please take note that when /CS is taken high, the DRDY pin is tri-stated. Therefore, the DRDY pin will not indicate the end of conversion. If you want to use a single SPI controller on your multiple ADCs please refer to this thread https://ez.analog.com/data_converters/precision_adcs/f/q-a/26356/how-do-i-interface-to-multiple-ad779x-adcs-over-the-same-serial-interface for further information.

I would suggest to use a single MCLK for the multiple devices, meaning one ADC can use its internal clock and output this to use as MCLK input for the other devices. In this configuration, you will ensure synchronization with multiple devices with a maximum of 1 MCLK difference only. So you only need to monitor the DRDY pin of the 1st device, when DRDY goes low, read its conversion, at this point the other ADCs will also available and you can read the conversion for other devices.

Thanks,

解决的方案是，读取特定ad7793的转换完成标志位，芯片寄存中有特定的寄存器可以检测，因此相对来说，没有读取引脚电平快，但是也是一个解决方案。
其实，某种程度上，如果是用片选来切换ad7793，那么用多路开关来切合读取的adc通道，才是比较好的方式，多个ad7793显得浪费，软件上都是一个一个通道一次读取的，除非多个spi设备。