Hi Neil! I was really surprised at how fast the S-100 Z80 CPU boards went this time. I ordered extras well above the pre-orders and even those were gone in just days.
My plan is to do another S-100 Z80 CPU V2 board run but this time roll in the minor tweaks from the S-100 VDP and S-100 Utility board projects. They don’t change any functionality but will make MSX integration a lot easier like using the V9938 CPU clock signal and allowing the Z80 to boot from external ROM with just a few jumpers. In addition, due to the volume of boards last year PayPal is becoming problematic. They cannot distinguish between a group hobby project and a business and it is causing me headaches and paperwork. In 2014 we will have to make different accommodations so the home brew computing project builders can do group PCB orders without all the PayPal hassles. Were we a local community group, all the interested builders would just throw cash into a “kitty” to do PCB orders and it would work smoothly since it is a group hobby project not someone’s business venture. However once PayPal gets involved they cannot distinguish the difference and it gets all screwed up. I am still figuring out how to make this work and will let the builders know once I have a workable plan. In the meantime if builders need a PCB and just cannot wait they are welcome to sponsor their own PCB manufacturing orders and distribute the boards to the group. Builders have been doing this on the N8VEM ECB side for years but for some reason it has never taken ahold with the S-100 builders. I will am happy to help any builder set up their own PCB order and walk them through the process. It is remarkably easy to do. If someone is really “champing at the bit” for a particular PCB maybe this would be a good opportunity for a test run. Thanks and have a nice day! Andrew Lynch From: [email protected] [mailto:[email protected]] On Behalf Of nbreeden Sent: Tuesday, February 4, 2014 9:58 PM To: [email protected] Cc: [email protected]; [email protected] Subject: [N8VEM-S100:2301] Re: accepting pre-orders for the S-100 Z80 CPU V2 board Andrew, Please put me down for one. -Neil On Sunday, January 5, 2014 12:39:03 PM UTC-8, lynchaj wrote: Hi! We are about to do another run of our popular S-100 Bus Z80 CPU V2 board. This board can run in systems (with bus termination etc.) at up to 10MHz. Apart from all the then common features found on many older S100 Z80 boards (and being completely S-100 IEEE-696 compliant), it had an extremely clever and powerful ability to allow the Z80 to address up to 1 MG of RAM in 16K "windows" within the Z80's address space. This is described here:- http://www.s100computers.com/My%20System%20Pages/Z80%20Board/Z80%20CPU%20Board.htm Its primary importance is that it can be used to address greater than 64K of RAM for CPM3 and that it can be used to load/examine 8086 code at the top of the 1MG address space. The new “V2” version of the board now has the ability to (under software control) dynamically switch between two 4K blocks of code in its onboard 28C64 EEPROM (or EPROM) yet still only occupy 4K in the Z80’s 64K memory space. This in effect almost doubles the size of a possible Z80 monitor. The extra code (currently being written) will include things like directly downloading binary files from a PC into the Z80’s 64K (or 8086’s 1M) address space. In addition, the S-100 Z80 CPU V2 has the ability to use an external CPU clock from an external source (S-100 bus pin 66 aka NDEF3). This is essential for CPU to video synchronization for MSX compatibility particularly in games. There will be a corresponding ability to export a CPU clock signal on the next version of the S-100 VDP board although this could come from any S-100 board. Current owners of the V1 board can just switch the IC’s to this new bare board. The S-100 Z80 CPU V2 PCBs will be $20 each as per the usual arrangement. Shipping in the US is $3 for a single PCB and $2 for each additional PCB. Shipping internationally is $12.75 for a single PCB and $3 for each additional PCB. This is for the bare basics USPS first class postage with no tracking or insurance. The builder assumes all risk of delivery as per usual arrangement. My preference is to sell these PCBs to vintage computer/home brew computer/classic computer hobbyists first but if there are any remaining boards I will put them on eBay. Please send a PayPal to [email protected] <javascript:> with the subject “S-100 Z80 CPU V2 board” and I will reserve your board(s). I need about 20 pre-orders to warrant a manufacturing run. I will post more information as it becomes available. Thanks and have a nice day! Andrew Lynch -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
