In the "Users Manual:Rabbit 6000 Microprocessor" section 35.3.3 (I2C peripheral:Master mode,Data write) ,the second step:Set the target slave address and R/W bit by writing to SGDR,I want to ask how to write the address byte to the SGDR register by Dynamic function,if like this WrPortI(SGDR,&SGDRShadow,0x70) ,the project compile have the error,why?