Make this controller an Xwire slave and use the configuration data table stored at address pppp in NVEM page 0.
For example:
XwireSlave pXWSlaveTable
NVEM0
pXWSlaveTable
NV0Byte TxRAMStart,TxRAMLength,RxRAMStart,RxRAMLength
Dialect restriction: This instruction is not implemented on boards prior to dialect D=20.