There are a number of subroutines that use SCH_SetCommand to send specific commands to the SX10509. Most are quite trivial. Here’s one of them:

;----- Send GET command to SCH
;      sSCH_GotEchois set once the command is echoed by SCH
SCH_Get:
        LoadX           kCMD_DoGet
        GoSub           SCH_SetCommand
        Return

There are several that follow the same pattern. They make it easier to code the higher level stuff, and make the program a lot more readable.

The subroutine for commanding a read from the SX10509 network Rx buffer is a bit more interesting. It is designed to use an offset, passed to it in the I (index) register, as a parameter in the command being sent to the SX10509. The Read command is documented here.

;----- Read from n/w Rx buffer in SCH to Xwire Rx data block
;      Starting offset in I
;      sSCH_GotEchois set once the command is echoed by SCH
SCH_Read:
        ItoX
        Store           bTxLength             ;Incremental offset
        LoadX           kCMD_Read
        GoSub           SCH_SetCommand
        Return