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I bought this board from eBay 5-6 years ago but got distracted with other projects. It looks like a complete Z80 SBC with Z80, SIO, CTC, 2732 and 6116. It is Allen Bradley 636021. Does anyone know more about it before I power it up? Bill

I have several tubes of this IC. According to Google, this is COPC881-TTB/N 20TWP1 Rev.0 from Tandy Corp, a replacement part for TRS-80. Can anyone provides more information? Thanks, Bill

I'm moving from a homebrew serial port based CP/M computer to a standalone Z80 CP/M computer with keyboard and text display. I think I know how to add the text display in the console output BIOS where the data go to both serial output and video display output. However, how do I combine both...

I recently designed a minimalistic, but CP/M-ready Z80 SBC. The motivation is to build a high performance CP/M computer kit for $20. To save cost, I use the CF disk as boot EPROM. To initialize a blank CF disk, I have a simple serial port that loads succession of software that finally wrote...

I've developed a 68030 homebrew. I'm interested in porting Linux for M68K. Can anyone provide current status of Linux-M68K and whom to contact? Thanks Bill

I recently acquired a batch of DiskOnModule (DOM) and upgraded my homebrew Z80 with DOM instead of compact flash. I'm curios about the performance difference between DOM and CF, so I made up three files each a megabyte in size and PIP them from one drive to another drive. With CP/M 2.2, CF...

I am developing a couple new Z80 SBC hardware. The first design works; CP/M2.2 and CP/M3 were successfully ported to it. The second design is closely related to the first except the serial transmit hardware is replaced with software bit banging function. The 2nd design works with a simple...

Does anyone have a copy of Super Micro Magazine issue #2 that should have an article featuring detailed design of a Z280 on S100 card? George Warner is the designer. Bill

I designed a CP/M-ready 68000 SBC for RC2014 bus. The SBC has 2 meg of memory. I like to partition the memory into TPA and RAMdisk. I'm thinking of 640KB for TPA and the remaining memory for RAMdisk but I don't know if 640KB TPA is sufficient for all known CP/M-68K applications. Does anyone...

I am developing a SBC based on the Z280 operating in the 16-bit Z-BUS mode. To save the cost of two boot ROM and to simplify the process of reprogramming the boot software, I have an unusual way of booting up the Z280 via CF drive: At power up or reset, a state machine in CPLD holds Z280 in...

Z280 has a 16-bit wide data bus so data structures should be aligned to word boundary (even address) for optimal performance. Right now I look at the listing and reserve a byte when needed to adjust the data structures to word boundary. My question is how to find out the address of buffers...

I'm working on a homebrew Z280 computer that has no ROM but boot out of compact flash instead. The cold bootstrap code is small, about 128 bytes, that copies a CF loader into memory and execute which, in turn, load & execute bigger program. My question is where to put the cold bootstrap code...

I'm new to Z80. I'm bring up a new board based on Z280. I want to use the UART bootstrap capability of the Z280 to serial load a small boot monitor (256 bytes max) which, in turn, loads a full feature monitor. I do want to learn Z80 programming, but right now I have many unknowns and it is...

On comp.os.cpm someone revived an old post about web brower for CP/M. https://groups.google.com/forum/#!topic/comp.os.cpm/292UdtpnAWc While that's a crazy idea for CP/M-80/86, I wonder if that's a do-able for CP/M68K? Being new to CP/M and not much of a software programmer, I can only ask...

Hello, I'm a retired hardware engineering who'd worked on embedded 680x0 products during the 80's and 90's. I want to revisit the 680x0 in my retirement and expand my knowledge to the desktop environments. --Bill

A decade ago I purchased a box of salvaged single board computers based on Motorola MC68302. They were made by ADC Communication as a controller for their Soneplex communication product line. I'd had no documentations but I figured out how to turn on the power and observed the outputs of console...

Dug out this S100 system in the back of my garage that I purchased in the early 1980's. I remember only used them briefly. I have not power it up since. One of the three boards is Cromemco 32K Bytesaver. I don't have any information about the two of the boards. Can anyone tell me more about...

I have half dozen of this part, RCA/SSTC TCC 180 A-E. The date code indicates it is made in 1975. I can not find any reference about it online. Can someone with RCA databook circa 1975 look it up for me? Thanks!