write method
Implementation
Uint16List write(){
if (readData == null) throw Exception('Must read data from device before write data');
var data = readData!.sublist(0);
for(RegisterField field in fields.values){
var d = data.sublist(field.offset,field.offset + field.size);
field.write(d);
data.setRange(field.offset, field.offset + field.size, d);
}
writeData = data;
return data;
}