What I learned.
The RC-6-28 has a complicated structure.
It is a bi-phase signal, which means that a 1 is represented by a +450, -450 timing pair and a 0 is -450+450 timing pair, where + timings mean that there is IR activity, and – times represent quiet times. But the RC-6 family of signals also have some structural timings inside the signal as well. So if you are looking at this on a graph, some of the bumps are 450 wide, others are 900 wide, but if you were to divide this up there are places where there are that around the 4th bit where its neither a zero, nor a 1. That is a structural timing .
The "Simple" approach to this is to describe the signal where each bit represents a single 450 splice of time. To do this a 1 represents a +450,-0 timing pair, the 0 is a +0,-450 timing pair. Then we jump to the IR engine and let it do all the work. This "Simple" approach doubles the number of data bits required to describe the signal, but eliminates having to program the logic in for those structural timings. This "Simple" approach works fine in both S3C8 and HCS08 engines for shorter signals like the RC-6-24, but the S3C8 balks when the number of data bytes required to transmit the signal is more than 8, we have demonstrated the the HCS08 will work with 9 bytes of data without a problem.
I adapted Rob's protocol for my "Simple" version of the SC308 protocol. Its not nearly as small as the HCS08's version, but at 32 instructions, it still saves you about 8 bytes over the full blown version of the protocols. The fewer instructions loaded into the remote, the more savings.
I added the RC-6-28 (Simple) to the protocol files.
https://www.hifi-remote.com/forums/dload ... e_id=13977
The Sky Q Box that has HCS08 support is in the Satellite Upgrades
https://www.hifi-remote.com/forums/dload ... e_id=13970