How do I use RU to access SIO?

RU removed the SIO auto-detection because it is out of date (Updated: auto-detection is back: here).  However you can still access the SIO chip manually.  Usually you have to enter configuration mode for accessing SIO registers.  RU will call open config before accessing each SIO register and then close config.   You can use CTRL-O and CTRL-Y to instruct RU to do open and close config.  Here is an example how to read a SIO chip:

1. ALT-2: ISA
   Select Index and Data port= 2e and 2f
2. CTRL-O to open config (enter config) for SIO chip
   List the commands here to open config like:
   
   o 2e 87
   o 2e 1
   o 2e 55
   o 2e 55
   So the configuration sequence 87h,01h,55h,55h will be sent to port 2eh before read/write register.
   Update: You can use a more convenient way now:
   o 2e 87 1 55 55
3. CTRL-Y to close config
   
   o 2e 2
   o 2f 2
   Then index 2 register will be set to 2 (BIT1=1) to close the config.

RU will call OpenConfig -> Read/Write register -> Call CloseConfig.
p.s. I plan to add back SIO auto-detection but it will take some time (which I don't have now).