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Obscure Microbee Hardware Enhancements - someone - 21-11-2019
There is a cache of microbee enhancements and additions that were obscure or never released.
Here are just two examples:
The Z80 CTC (Counter/Timer Circuit).
Originally present on the DGZ80 but due to the cost constraints of the original microbee it was omitted.
The microbee I/O port decoding provides provision for a CTC at port address 0x04-0x07.
Having a CTC present greatly enhances a microbee's capability by removing its reliance most limiting factors - software derived timing and software device polling.
The Enhanced Floppy Disk Controller with multiple serial ports and and battery backed Real Time Clock.
This used Signetics 2651 USARTs to provide fully fledged interrupt driven RS232 ports.
RE: Obscure Microbee Hardware Enhancements - someone - 23-11-2019
There is a full speed SPI compatible interface for the microbee that was originally designed and made in the mid 1980's as a mouse interface.
It is connected using the 50 way expansion interface.
These days it is a very useful way of attaching modern SPI peripherals and MMC/SDCards to a microbee to make experimenting with a microbee easy and fun.
Driving SPI peripherals can be easily accomplished with just a few simple MWBASIC IN and OUT statements so who needs a Arduino Sketch when it can be done with microbee?
RE: Obscure Microbee Hardware Enhancements - MbeeTech - 25-11-2019
(23-11-2019, 01:20 PM)someone Wrote: There is a full speed SPI compatible interface for the microbee that was originally designed and made in the mid 1980's as a mouse interface.
It is connected using the 50 way expansion interface.
These days it is a very useful way of attaching modern SPI peripherals and MMC/SDCards to a microbee to make experimenting with a microbee easy and fun.
Driving SPI peripherals can be easily accomplished with just a few simple MWBASIC IN and OUT statements so who needs a Arduino Sketch when it can be done with microbee?
Hello Someone.
I'm sure this would be handy & a bit of fun to add.
Would you be able to put together a rough schematic & port map?
Thanks!
RE: Obscure Microbee Hardware Enhancements - someone - 10-12-2019
Someone has come commentary and a photo but does not currently know how to post a photo in this forum yet.
Tried cutting and a pasting a graphic but there was a size error.
RE: Obscure Microbee Hardware Enhancements - MbeeTech - 11-12-2019
(10-12-2019, 08:31 PM)someone Wrote: Someone has come commentary and a photo but does not currently know how to post a photo in this forum yet.
Tried cutting and a pasting a graphic but there was a size error.
Hello Someone.
There is an icon to insert a picture above the post editing text box.
Currently picture files are limited to 500KB. If your image file size is bigger than that, let me know & I'll change the settings for that file type.
Regards,
RE: Obscure Microbee Hardware Enhancements - longi - 20-12-2019
(21-11-2019, 08:38 AM)someone Wrote: The Enhanced Floppy Disk Controller with multiple serial ports and and battery backed Real Time Clock.
This used Signetics 2651 USARTs to provide fully fledged interrupt driven RS232 ports.
An RTC would be awesome. Opens the door to things like https://en.wikipedia.org/wiki/SymbOS
RE: Obscure Microbee Hardware Enhancements - Ernest - 20-12-2019
(20-12-2019, 06:05 PM)longi Wrote:The Premium and 256TC already have RTC capability built in and was able to be added to most of the earlier systems with a hardware upgrade.(21-11-2019, 08:38 AM)someone Wrote: The Enhanced Floppy Disk Controller with multiple serial ports and and battery backed Real Time Clock.
This used Signetics 2651 USARTs to provide fully fledged interrupt driven RS232 ports.
An RTC would be awesome. Opens the door to things like https://en.wikipedia.org/wiki/SymbOS
RE: Obscure Microbee Hardware Enhancements - someone - 21-12-2019
(20-12-2019, 08:52 PM)Ernest Wrote:(20-12-2019, 06:05 PM)longi Wrote:The Premium and 256TC already have RTC capability built in and was able to be added to most of the earlier systems with a hardware upgrade.(21-11-2019, 08:38 AM)someone Wrote: The Enhanced Floppy Disk Controller with multiple serial ports and and battery backed Real Time Clock.
This used Signetics 2651 USARTs to provide fully fledged interrupt driven RS232 ports.
An RTC would be awesome. Opens the door to things like https://en.wikipedia.org/wiki/SymbOS
The Alpha Plus(aka Premium) and 256TC were created after the Enhanced Floppy Disk Controller. The Enhanced Floppy Disk controller was not released due to an SRAM shortage and market release of 64K x 1 DRAMs of the time which led to the creation of the more inexpensive 128K DRAM FDC coreboard. The initial coreboards supported both Z80 and TMS4500 DRAM controllers. Since these this new coreboard had a FDC connector and no 50 way expansion connector, the Alpha Plus baseboard was laid with the 50 way expansion connector. There is also a mod board for standard baseboards to have a 50 way expansion connector.
Seasons' Greetings!
Have a safe and festive holiday period.
RE: Obscure Microbee Hardware Enhancements - ChickenMan - 24-12-2019
It would be awesome to see the SymbOS system running on a Prem 128k, 256TC or better still the PP+ or the new to be released Classic +.
http://symbos.de/index.htm
RE: Obscure Microbee Hardware Enhancements - MbeeTech - 24-12-2019
I've been interested in SymbOS for a number of years now, since the first time someone (no, not our member 'Someone') first brought it to my attention.
The first hurdle would be lack of a timer in the older models, but this could quickly be overcome by using an interrupt generated by VSync linked to a PIO pin
like what has been done on the PC85 for a psuedo RTC.
It would be good to implement it on the Premium Plus & 256TC-SE as they have 1Mbyte ram.
Monochrome 640 x 256 resolution would be o.k. (I don't think SymbOS would lend itself to Colour per Character well).
Not saying too much about it at this stage, BUT, the Classic Plus (yes it is being worked on) will be much more suitable graphics wise.
Looking over the SymbOS website though, it appears not to be open source, nor are there any contact links to try and encourage a port along.