I am using three serial-to-USB chips (CH34xxx) to a USB hub chip on a project. The three CH34xxx are simply powered and connected to the USB hub chip, and everything works fine, but they show up as "random" devices (/dev/tty.wchusbserial14210, 14220 and 14230). I would like to delay them so they power up in a sequence, so 14210 ALWAYS is serial port 1, 14220 is port 2 and 14230 port 3.
Any cheap and reliable techniques out there?
The first CH34xxx don't need delay, the second needs some and the third needs even more. I was thinking about adding a series resistor -> a medium capacitor (in addition to the mandatory 100nF) to the VCC of second CH34xx, and an even larger cap for third CH34xx.