The original HCS-II uses a Z80180/64180 processor that runs at 9.216 MHz. When the board was originally designed, memory was not very fast, so the HCS-II inserted 1 ‘wait state’ during every memory access. Wait states are delay cycles to allow slow memory time to access the requested data and return it. This combination has worked well for years in thousands of homes. However, as Home Automation installations get more complex, they require more performance from their controllers. Those of you with large XPRESS programs may have noticed subtle things like second timers which aren’t always precise, slower response to direct digital inputs, slow network response, etc. This is due to the speed of the CPU and the time it takes to access the RAM and EPROM. In some installations the delays were very noticeable and affected smooth operation of the XPRESS control program.
Thanks to a new CPU developed by Zilog, we have put together an upgrade kit for HCS-II controllers. This upgrade kit will double the processing speed of your HCS-II so it runs at 18.432 MHz instead of 9.216 MHz. It also includes faster RAM and EPROM chips which allow for the elimination of the memory wait state. Combined, these improvements boost the performance of your HCS-II by about 2.5.
The upgrade kit includes a new Z8S180 CPU, 2 high speed 32K RAM chips, 1 high speed EPROM with XPRESS v4.0, a DIP chip extraction tool, a PLCC extraction tool, a disposable static strap, and a documentation CD. You can also view the upgrade instructions online.
v4.0 of XPRESS has the same feature set as v3.x, however v4.0 contains numerous modifications required to accommodate the faster CPU speed. v3.6x firmware will NOT work properly with the new Z8S180 CPU.
The upgrade can be used on both HCS-DX2 and RTC-180 circuit boards. No circuit board modifications are required! You simply remove the CPU, RAM and EPROM chips using the provided tools and replace them with the newer versions. Recompile your existing XPRESS program and your back in control with a faster HCS-II controller.
Obvious improvements from this CPU will be seen in the accuracy of the seconds timers, the network is faster (It is still 9600 baud, but the HCS-II processes incoming packets MUCH faster so it can send out the next packet faster), and overall response to local inputs is faster.
HCS-II Processor Upgrade FAQ
- My HCS-II board has an 18.432 MHz crystal - why should I upgrade? All HCS-II boards have 18.432 MHz crystals. However, the CPUs only run at 9.216MHZ because the original Z80180/64180 processors divide the clock by 2. Thus the CPU itself runs at half the crystal speed. The new Z8S180 CPU runs at the actual crystal speed. The upgrade also removes the wait state inserted before RAM and EPROM accesses. This improves performance as well.
- I have v3.6x of XPRESS - can I just buy the CPU? No. v3.6x of XPRESS does not have the many modifcations necessary to use the Z8S180 CPU. The board will come up, but it will still run at 9.216MHz and you will have serious network problems as the Z8S180 uses a new type of UART with a bigger buffer which required significant firmware changes in v4.0
- Can I store larger XPRESS programs with this upgrade? No. This upgrade includes 32K Static RAM chips which are the same size as your existing RAM chips, except they are much faster (70ns vs 120-150ns) Utilizing bigger RAM chips would require modification to the circuit board to accomodate the additional address lines.
- What types of improvements will I see with this upgrade? There are numerous improvements when you upgrade, some obvious, some not so obvious:
- Second Timers are more accurate in complex XPRESS programs
- Your XPRESS program will run 2.5 times faster which means it will respond to changing inputs faster
- The network is faster. It still runs at 9600 baud, however, the HCS-II processes the incoming packets much faster so it can send the next query/command out faster. In other words, the delay between network responses and network queries/commands is shorter.
- The RS-485 UART buffer has been expanded allowing more time for XPRESS tasks instead of emptying the serial buffer to prevent packet loss.
- I have an older RTC-180 HCS board - can I upgrade this type of board? Yes. This upgrade will work with both HCS-2DX and RTC-180 HCS controller boards. Note that you should leave the SmartSocket/Real-time clock assembley in place and just swap out the RAM chip. If the SmartSocket is not used after the upgrade, you will have no way to keep time as the real-time clock is embedded in the SmartSocket.
- I bought this upgrade and installed it, but now my RTC-180 controller is unstable and locking up. What is wrong? Users with RTC180 boards have reported problems with their systems after installing the new CPU. Apparently, the 74LS245 bus drivers used on the RTC180 board cannot handle driving more than one or two stack boards, especially if one of the boards is an HCS-DTMF or an HCS-Voice. Symptoms of this problem are the board not allowing a program upload and the board seeming to ‘reset’ on its own. This problem is EASY to fix. Email us at support@cc-concepts.com and ask for 2 74HCT245 ICs. We’ll send them to you right away. Just replace the 74LS245 ICs you currently have with these newer CMOS based version which can handle bigger bus loads. This will make your troubles go away.
- Is v4.00 of XPRESS different than v3.63? Internally it is, however externally users will notice no difference. The v4.00 XPRESS firmware is different from v3.63 in that it includes numerous changes to handle the faster and more advanced Z8S180 CPU. However, from a user’s point of view, the XPRESS language is UNCHANGED when comparing v3.63 and v4.00. Any program written for v3.x of XPRESS will run on v4.0x.
- I have an RTC-180 board and now I can’t upload my control program after performing the upgrade. This is a known problem due to the 74LS245 ICs on RTC180’s not being able to drive more than one or two stack cards at the higher frequency the S180 CPU uses. See the above FAQ item about RTC-180 instability. Request a bus IC update via email and we’ll send them to you right away.
