Ни%я непонятно, но очень интересно так не пойдёт?
typedef union R4container
{
unsigned long data;
unsigned char _8_bit_data_[4];
struct
{
unsigned int select:3;
unsigned int outPwr:2;
unsigned int outEnable:1;
unsigned int auxmodes:4;
unsigned int muteTillLock:1;
unsigned int VCOpowerdown:1;
unsigned int bandSelClkVal:8;
unsigned int RFdivSelect:3;
unsigned int fedbackSel:1;
unsigned int :8;
}bits;
}R4container;
...
R4container _R4datareg;
...
_R4initMask_={.bits.RFdivSelect=0,.bits.auxmodes=0,.bits.VCOpowerdown=0,.bits.muteTillLock=0,
.bits.bandSelClkVal=8,.bits.fedbackSel=1,
.bits.outEnable=1,.bits.outPwr=3,.bits.select=4};
...
_R4datareg.data=_R4initMask_.data;
...
port0=_R4datareg._8_bit_data_[0];
port1=_R4datareg._8_bit_data_[1];
...