BBC + Master online (fork from ElkWiFi)

discuss both original and modern hardware for the bbc micro/electron
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roland
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BBC + Master online (fork from ElkWiFi)

Post by roland » Wed Sep 09, 2020 10:39 am

I forked this topic from the ElkWiFi topic to keep things a bit separated and clear.

As it looks now, a Master version of the ElkWiFi will take some time. I agree with Hoglet to focus on the Electron first. Soon I am going to release the source codes, except for the KiCad files. The reason for that is that I want to avoid that this design gets copied and sold on Ebay.

However, if somebody feels brave enough to modify the design and software so that it will work in a Master then I am very cooperative and will share the KiCad files under strict conditions. In short: it won't cost money but the brave person should also not make money from it. A small margin for covering development costs is all right for me.

Having said that, there might be another way to connect the ESP8266 to a Beeb or Master. Both computers have a serial interface so you only need a converter from the RS423 signals to the 3.3V levels of the ESP8266. There is already room for a ROM in those computers so the only thing lacking is the 64kB/128kB paged RAM. This memory is mainly used for buffering the incoming data; if there are other sources of memory those can be used as well. For example, my Beeb has a 256k RAM board so there should be some usable memory. Another way could be using just a small buffer and download only small amounts of data; most modern web servers support partial transfers of files.

So there are a few ways to investigate to get a Beeb or Master online with an ESP8266. Who is brave enough to start this project?
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
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Re: BBC + Master online (fork from ElkWiFi)

Post by 1024MAK » Wed Sep 09, 2020 3:54 pm

My thoughts are this: although the cartridge slots on the Master 128 are useful, when I use them on my machines, it’s normally only for ROM cartridges or RAM/ROM cartridges (and sometimes a dirty contact can cause the machine to crash).

For interfaces, I think they are better being on the 1MHz bus. Then they can be used by BBC B, BBC B+ and Master 128 machines. Note that a Master Compact has no cartridge slots and has no 1MHz bus. Although it does have an expansion bus.

As noted in the original topic (Acorn Electron online? Any such hardware.), the I/O hardware memory map is not exactly the same. In particular, the sideways ROM latch is slightly different in operation and lives at a different memory location.

Additional RAM can be included in a 1MHz bus interface.

So to sum up, if a BBC / Master version is developed, I think it should be connected to the 1MHz bus rather than being a cartridge.

Mark

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Re: BBC + Master online (fork from ElkWiFi)

Post by roland » Sat Sep 19, 2020 7:21 am

Sweet dream or nightmare? This morning I woke up with the idea to usethe RS232 TTL adapter (from WiFi printing) in combination with the ESP8266 module from the Electron. That could create the necessary WiFi hardware for the Beeb and the Master.

I added extra RAM to the Electron because it has slow RAM. The BBC and Master have fast RAM and many systems have sideways RAM that we can use as a buffer. Sideways ROM is no problem also. So that can make a simple setup. The only thing is that the amount of buffer RAM is a bit limited which can limit some features like WiCFS.

Who has enough time to start this project :wink: ?
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Re: BBC + Master online (fork from ElkWiFi)

Post by hoglet » Sat Sep 19, 2020 7:32 am

Would this connect to the RS423 port on the Beeb/Master?

That would limit the speed (I think) to 19,200 baud.

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Re: BBC + Master online (fork from ElkWiFi)

Post by Alan00 » Sat Sep 19, 2020 8:29 am

Hi,

I have made an adapter PCB so I can have the ESP8266 inside my BBC.

The serial ULA plugs into the PCB and the PCB plugs into the serial ULA socket and the ESP8266 PCB sits on top.
This ESP8266 PCB takes 5V TTL serial and also has a 5V to 3.3V regulator so no extra wiring.

As Commstar only goes to 9600, I have not tried 19200 but it should work at 19200
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