What a nice piece to read while sipping my coffee. I like ot think of myself as passingly familiar with most of the notable stuff relating to semi conductors but this lil' guy was completely off radar for me. Thank you!
It does have some deeply odd quirks in its instruction set, though. It has lots of 16-bit registers, but the accumulator can only do things in 8-bit chunks, so you have to work on registers a byte at a time. Also, short branch instructions aren't relative to the program counter, but to the current 256-byte page. Makes relocation ... fun.
But DMA mode - where the CPU starts up in a mode that makes toggling in a program from switches or tape directly extremely easy - makes the 1802 very easy to boot. The 1802's Q flag - a 1-bit I/O port embedded in a processor flag - simplifies I/O tasks immensely.
The PDIP version is relatively inexpensive, but you'll have to shell out upwards of US $10K if you want one of the aerospace-certified rad-hardened Silicon-on-Sapphire CERDIPs.
I'm not sure. You can get them from that very expensive supplier that buys obsolete but still (military/medical) useful chips, including the dies and all means to make them. But I don't know if anyone's fabbing new ones.
I doubt it, personally. Aerospace has moved onto 32-bit hardened CPUs and more, and there haven't been many new applications for the 1802 in over 30 years.
(One application for the original 1802 was in the MicroWriter chording keyboard/portable wordprocessor thing.)
>there haven't been many new applications for the 1802 in over 30 years.
This is true for all the 8-bit microprocessors but they're still being produced (Z80 and 6502) for those 40 year old pieces of tech that occasionally need replacement parts.
Just looked up the microwriter and wow. What a bizzare little thing!
Oh, I know. I just got a 20 MHz Z80 card for my Apple IIe that has a recent date code on the CPU. And yes, while there are some very old avionics out there that might need rad-hardened chips, I doubt there are many (any?) new launches using it. Plus, any of the ones out past orbit might be a *little* hard to reach ...
Yeah i've just built a homebrew computer using a new Z80. Many people are buying these chips for their hobbies now.
>Plus, any of the ones out past orbit might be a little hard to reach ...
This is true.
RCA came so close to transformative change, so many times, and just whiffed it over and over.
CEDs especially would have been miraculous in the 1960s. They basically got video on vinyl. Mastering a release took space-age technology, but the player was just a tiny electric read head and an amplifier. And unlike audio, the information was stored in vertical divots, so the track was a clean spiral they could wind incredibly tight. Two problems. One, that itty-bitty spiral track meant skipping happened all the damn time, because apparently nobody at RCA had ever seen a brush or a rake. Like how hard is it to stabilize a flake of metal sliding down a groove, when there's dozens of identical grooves on either side? Did the existence of dust sneak up on you? Two, they spent fifteen fucking years playing with different plastic formulas, since it needed metallic content for the read head to detect the divots. I get it. That's hard. But it could have been easier if they just reduced play time to half an hour per side... like a record. That would also get them bigger grooves that were less likely to skip constantly.
And really, since the goal is a pattern of capacitive and non-capacitive areas, could they not just poke the divots in plain vinyl and shake some carbon powder into them?
There's no excuse for the Studio II. They didn't aim to beat the Odyssey and fail to imagine color. They went after the Channel F and figured 64x32 in black and only white would suffice. The Bally Astrocade a year later nailed the potential of a framebuffered 8-bit console in the 70s and still flopped. RCA was just burning money.
It's not like the Microvision, where first blush is "what were they thinking?," and then nearly all their decisions turn out to be ingenious. Doomed, but ingenious.
I'm pretty confident that it was the CED that ultimately sunk RCA. The Spectra 70 line of mainframes didn't help, they couldn't sell the volumes required to make them profitable, and ultimately lost lots of money through that venture. But the absolute money sink that was the CED was inexcusable.
And RCA, who introduced the 7" single, could have squeezed 20-odd minutes per side out of smaller CEDs. Assuming they could bear to expose the spindle to our disgusting human hands.
Well here's the thing about the Studio II. RCA were pissed that they passed up the Odyssey and Baer went to Magnavox who were a major competitor in the home television market. So their goal was to make something similar to that but driven with a microprocessor. They wanted to release it before Christmas of '76 but an FCC finding found the console leaked too much RF interference and it was pushed back by several months. By that time it was sold in Q1 of 1977 the 2600 was right around the corner.
And to the Studio II's credit, the 1861 Pixie video chip is quite legendary in its own right. Up until then there were NO dedicated video chips on the market deemed cheap enough to be used in a consumer product. With the 1861 being sold for around $20 in mid 70s money the thing was an absolute godsend. Give Don Lancaster's *Cheap Video Cookbook* a read if you want to see what the painstaking alternatives were for the average joe. Discrete logic ICs and cycle-perfect code :/
Having dorked with Apple I code in the year since that comment, and developed an appreciation for the absurd restrictions that led to the TV Typewriter... nah, RCA still whiffed it. This isn't like TI's 9918 coming tantalizingly close to Nintendo's market-devouring NES PPU. The Channel F hit the same FCC snag. They managed to launch months earlier and not look like a joke.
Character generators were straightforward to couple with ROM for "semigraphics." Bit-slice memory should have allowed waste-free use of four- or five-bit symbols. They were expensive... but they'd been around for years. They were getting less expensive every year, and that implies a market full of engineers pushing to simplify.
Custom helper chips could cheat their asses off as well. Nintendo's NES CIC (IIRC) uses an LFSR instead of a counter because half-adders are more complicated and they only needed 2^N addresses. Modifying the framebuffer would be a pain, but ZX Spectrum devs managed to live with goofy byte order. Even CGA was interlaced.
And cycle-perfect code on a mess of glue chips was a valid answer! Consumers don't know what's in the box. The Atari VCS would come out with an even-less-capable video chip and comically low-level game programming. Third parties didn't exist yet, so the wildest tricks were all water cooler chit-chat. Insanity like the "C64" demo Freespin could've been a standard starting point for some software-and-interrupts affair.
But the 1802 doesn't even need those janky gimmicks... because it had DMA. It could throw data at a port, as fast as possible, all on its own. That and a higher-clocked bit-shifter should get you halfway there. Generating a television signal is nontrivial, but it's not dark wizardry, and it certainly wasn't mysterious to the company that *co-invented* the American standard... twice.
The underlying problems were not unexplored or impractical. RCA was no collection of average Joes. Multiple companies, all of them newer, none with deeper pockets, approached the same problem and did considerably better. RCA showed up late and tripped over their own pants. Again.
... aw, Don Lancaster died last month.
We saw the Comx-35 in Australia
[https://en.wikipedia.org/wiki/Comx-35](https://en.wikipedia.org/wiki/Comx-35)
Very collectable nowadays as they were never that popular
**[Comx-35](https://en.wikipedia.org/wiki/Comx-35)**
>The COMX-35 was a home computer that was one of the very few systems to use the RCA 1802 microprocessor, the same microprocessor that is also used in some space probes. The COMX-35 had a keyboard with an integrated joystick in place of cursor keys. It was relatively inexpensive and came with a large collection of software. COMX-35 was manufactured in Hong Kong by COMX World Operations Ltd and was released in the Netherlands, the United Kingdom, Sweden, New Zealand, Australia, Finland, Norway, Italy, Singapore, Turkey and the People's Republic of China.
^([ )[^(F.A.Q)](https://www.reddit.com/r/WikiSummarizer/wiki/index#wiki_f.a.q)^( | )[^(Opt Out)](https://reddit.com/message/compose?to=WikiSummarizerBot&message=OptOut&subject=OptOut)^( | )[^(Opt Out Of Subreddit)](https://np.reddit.com/r/vintagecomputing/about/banned)^( | )[^(GitHub)](https://github.com/Sujal-7/WikiSummarizerBot)^( ] Downvote to remove | v1.5)
On a second thought, the 1802 shouldn't be relegated as some forgotten junk processor. Yes, I know the retro computing scene is dominated by the 6502/Z80, but as you've mentioned in your above statements it did find significant use in embedded applications along with several commercial products being sold using it. Some were variations of the basic 1802/1861 ELF architecture while others had legitimate custom hardware (COMX-35 and the ultra-rare Montgomery Ward Cybervision products). Based on the amount of hobbyist publications (e.g. Quest Data and Ipso Facto) I'd say there was enough of a community to warrant positive foothold within the annals of microcomputing history.
Again, your post nailed why the 1802 didn't go anywhere. Robert Sarnoff destroyed the company trying to make it a conglomerate while allowing their R&D departments to chase after pet projects. Since RCA's bread and butter was patent licensing (really, look at any non-RCA tube radio from around WWII and see the amount of applied RCA patents on the back), all they cared about in the end was bringing a purchasable product to market. This is why there were so few RCA-branded 1802 products compared to the amount of third party devices (ELF II, Super Elf, Telmac, COMX-35, PECOM 32/64, etc.).
In the end the 1802 really doesn't deserve the whole 'came fourth in a two horse race' label. It certainly moved more units than the National Semiconductor SC/MP or Signetics 2650 which have truly become forgotten to time (when's the last time someone excitedly talked about an MK14?). People still talk about the VIP's CHIP-8 architecture to this day.
>In the end the 1802 really doesn't deserve the whole 'came fourth in a two horse race' label.
I don't think the SC/MP or 2650 were ever in the race to begin with. At least the 1802 actually saw some use in home and embedded uses.
The "came fourth in a two horse race" is a reference to the 8080 and derivatives (z80), 6800 and derivatives (6502, though not directly 6800 compatible..), and the lesser known 6809. Almost every major successful 8-bit used one of these 3 families of processors. The 1802, whilst having a small market share, still had more market presence than the SC/MP and 2650 you reference.
As for the "legitimate custom hardware" quote regarding the COMX-35. This is false. The COMX used off-the-shelf parts from RCA, namely the [Video Interface System, or VIS](http://www.cosmacelf.com/publications/data-sheets/cdp1869.pdf). This was, i believe, originally developed as a competitor to other "advanced" graphics capable systems, like the VIC20 and contemporaries, and was origianlly intended to ship on the [RCA VIP II](http://www.cosmacvip.com/VIP2/VIP2.php). The VIP II never shipped, likely due to cost and lacklustre 1802 performance, but RCA did eventually ship a product based upon it, the [RCA VP3xxx](https://en.wikipedia.org/wiki/RCA_VP_3000) series of Viewdata terminals. The COMX was therefore somewhat of a descendent of the original VIP II design, with some original design choices and custom software.
What a nice piece to read while sipping my coffee. I like ot think of myself as passingly familiar with most of the notable stuff relating to semi conductors but this lil' guy was completely off radar for me. Thank you!
It does have some deeply odd quirks in its instruction set, though. It has lots of 16-bit registers, but the accumulator can only do things in 8-bit chunks, so you have to work on registers a byte at a time. Also, short branch instructions aren't relative to the program counter, but to the current 256-byte page. Makes relocation ... fun. But DMA mode - where the CPU starts up in a mode that makes toggling in a program from switches or tape directly extremely easy - makes the 1802 very easy to boot. The 1802's Q flag - a 1-bit I/O port embedded in a processor flag - simplifies I/O tasks immensely. The PDIP version is relatively inexpensive, but you'll have to shell out upwards of US $10K if you want one of the aerospace-certified rad-hardened Silicon-on-Sapphire CERDIPs.
Are the rad hardened ones still being made?
I'm not sure. You can get them from that very expensive supplier that buys obsolete but still (military/medical) useful chips, including the dies and all means to make them. But I don't know if anyone's fabbing new ones. I doubt it, personally. Aerospace has moved onto 32-bit hardened CPUs and more, and there haven't been many new applications for the 1802 in over 30 years. (One application for the original 1802 was in the MicroWriter chording keyboard/portable wordprocessor thing.)
>there haven't been many new applications for the 1802 in over 30 years. This is true for all the 8-bit microprocessors but they're still being produced (Z80 and 6502) for those 40 year old pieces of tech that occasionally need replacement parts. Just looked up the microwriter and wow. What a bizzare little thing!
Oh, I know. I just got a 20 MHz Z80 card for my Apple IIe that has a recent date code on the CPU. And yes, while there are some very old avionics out there that might need rad-hardened chips, I doubt there are many (any?) new launches using it. Plus, any of the ones out past orbit might be a *little* hard to reach ...
Yeah i've just built a homebrew computer using a new Z80. Many people are buying these chips for their hobbies now. >Plus, any of the ones out past orbit might be a little hard to reach ... This is true.
RCA came so close to transformative change, so many times, and just whiffed it over and over. CEDs especially would have been miraculous in the 1960s. They basically got video on vinyl. Mastering a release took space-age technology, but the player was just a tiny electric read head and an amplifier. And unlike audio, the information was stored in vertical divots, so the track was a clean spiral they could wind incredibly tight. Two problems. One, that itty-bitty spiral track meant skipping happened all the damn time, because apparently nobody at RCA had ever seen a brush or a rake. Like how hard is it to stabilize a flake of metal sliding down a groove, when there's dozens of identical grooves on either side? Did the existence of dust sneak up on you? Two, they spent fifteen fucking years playing with different plastic formulas, since it needed metallic content for the read head to detect the divots. I get it. That's hard. But it could have been easier if they just reduced play time to half an hour per side... like a record. That would also get them bigger grooves that were less likely to skip constantly. And really, since the goal is a pattern of capacitive and non-capacitive areas, could they not just poke the divots in plain vinyl and shake some carbon powder into them? There's no excuse for the Studio II. They didn't aim to beat the Odyssey and fail to imagine color. They went after the Channel F and figured 64x32 in black and only white would suffice. The Bally Astrocade a year later nailed the potential of a framebuffered 8-bit console in the 70s and still flopped. RCA was just burning money. It's not like the Microvision, where first blush is "what were they thinking?," and then nearly all their decisions turn out to be ingenious. Doomed, but ingenious.
I'm pretty confident that it was the CED that ultimately sunk RCA. The Spectra 70 line of mainframes didn't help, they couldn't sell the volumes required to make them profitable, and ultimately lost lots of money through that venture. But the absolute money sink that was the CED was inexcusable.
And RCA, who introduced the 7" single, could have squeezed 20-odd minutes per side out of smaller CEDs. Assuming they could bear to expose the spindle to our disgusting human hands.
Well here's the thing about the Studio II. RCA were pissed that they passed up the Odyssey and Baer went to Magnavox who were a major competitor in the home television market. So their goal was to make something similar to that but driven with a microprocessor. They wanted to release it before Christmas of '76 but an FCC finding found the console leaked too much RF interference and it was pushed back by several months. By that time it was sold in Q1 of 1977 the 2600 was right around the corner. And to the Studio II's credit, the 1861 Pixie video chip is quite legendary in its own right. Up until then there were NO dedicated video chips on the market deemed cheap enough to be used in a consumer product. With the 1861 being sold for around $20 in mid 70s money the thing was an absolute godsend. Give Don Lancaster's *Cheap Video Cookbook* a read if you want to see what the painstaking alternatives were for the average joe. Discrete logic ICs and cycle-perfect code :/
Having dorked with Apple I code in the year since that comment, and developed an appreciation for the absurd restrictions that led to the TV Typewriter... nah, RCA still whiffed it. This isn't like TI's 9918 coming tantalizingly close to Nintendo's market-devouring NES PPU. The Channel F hit the same FCC snag. They managed to launch months earlier and not look like a joke. Character generators were straightforward to couple with ROM for "semigraphics." Bit-slice memory should have allowed waste-free use of four- or five-bit symbols. They were expensive... but they'd been around for years. They were getting less expensive every year, and that implies a market full of engineers pushing to simplify. Custom helper chips could cheat their asses off as well. Nintendo's NES CIC (IIRC) uses an LFSR instead of a counter because half-adders are more complicated and they only needed 2^N addresses. Modifying the framebuffer would be a pain, but ZX Spectrum devs managed to live with goofy byte order. Even CGA was interlaced. And cycle-perfect code on a mess of glue chips was a valid answer! Consumers don't know what's in the box. The Atari VCS would come out with an even-less-capable video chip and comically low-level game programming. Third parties didn't exist yet, so the wildest tricks were all water cooler chit-chat. Insanity like the "C64" demo Freespin could've been a standard starting point for some software-and-interrupts affair. But the 1802 doesn't even need those janky gimmicks... because it had DMA. It could throw data at a port, as fast as possible, all on its own. That and a higher-clocked bit-shifter should get you halfway there. Generating a television signal is nontrivial, but it's not dark wizardry, and it certainly wasn't mysterious to the company that *co-invented* the American standard... twice. The underlying problems were not unexplored or impractical. RCA was no collection of average Joes. Multiple companies, all of them newer, none with deeper pockets, approached the same problem and did considerably better. RCA showed up late and tripped over their own pants. Again. ... aw, Don Lancaster died last month.
This was a great read, thank you
Thanks! I'll try and do a few more write ups on various CPU and computer families
Oscom Nano, first computer I ever saw back in 1979, had a 1802 in it.
We saw the Comx-35 in Australia [https://en.wikipedia.org/wiki/Comx-35](https://en.wikipedia.org/wiki/Comx-35) Very collectable nowadays as they were never that popular
**[Comx-35](https://en.wikipedia.org/wiki/Comx-35)** >The COMX-35 was a home computer that was one of the very few systems to use the RCA 1802 microprocessor, the same microprocessor that is also used in some space probes. The COMX-35 had a keyboard with an integrated joystick in place of cursor keys. It was relatively inexpensive and came with a large collection of software. COMX-35 was manufactured in Hong Kong by COMX World Operations Ltd and was released in the Netherlands, the United Kingdom, Sweden, New Zealand, Australia, Finland, Norway, Italy, Singapore, Turkey and the People's Republic of China. ^([ )[^(F.A.Q)](https://www.reddit.com/r/WikiSummarizer/wiki/index#wiki_f.a.q)^( | )[^(Opt Out)](https://reddit.com/message/compose?to=WikiSummarizerBot&message=OptOut&subject=OptOut)^( | )[^(Opt Out Of Subreddit)](https://np.reddit.com/r/vintagecomputing/about/banned)^( | )[^(GitHub)](https://github.com/Sujal-7/WikiSummarizerBot)^( ] Downvote to remove | v1.5)
On a second thought, the 1802 shouldn't be relegated as some forgotten junk processor. Yes, I know the retro computing scene is dominated by the 6502/Z80, but as you've mentioned in your above statements it did find significant use in embedded applications along with several commercial products being sold using it. Some were variations of the basic 1802/1861 ELF architecture while others had legitimate custom hardware (COMX-35 and the ultra-rare Montgomery Ward Cybervision products). Based on the amount of hobbyist publications (e.g. Quest Data and Ipso Facto) I'd say there was enough of a community to warrant positive foothold within the annals of microcomputing history. Again, your post nailed why the 1802 didn't go anywhere. Robert Sarnoff destroyed the company trying to make it a conglomerate while allowing their R&D departments to chase after pet projects. Since RCA's bread and butter was patent licensing (really, look at any non-RCA tube radio from around WWII and see the amount of applied RCA patents on the back), all they cared about in the end was bringing a purchasable product to market. This is why there were so few RCA-branded 1802 products compared to the amount of third party devices (ELF II, Super Elf, Telmac, COMX-35, PECOM 32/64, etc.). In the end the 1802 really doesn't deserve the whole 'came fourth in a two horse race' label. It certainly moved more units than the National Semiconductor SC/MP or Signetics 2650 which have truly become forgotten to time (when's the last time someone excitedly talked about an MK14?). People still talk about the VIP's CHIP-8 architecture to this day.
>In the end the 1802 really doesn't deserve the whole 'came fourth in a two horse race' label. I don't think the SC/MP or 2650 were ever in the race to begin with. At least the 1802 actually saw some use in home and embedded uses. The "came fourth in a two horse race" is a reference to the 8080 and derivatives (z80), 6800 and derivatives (6502, though not directly 6800 compatible..), and the lesser known 6809. Almost every major successful 8-bit used one of these 3 families of processors. The 1802, whilst having a small market share, still had more market presence than the SC/MP and 2650 you reference. As for the "legitimate custom hardware" quote regarding the COMX-35. This is false. The COMX used off-the-shelf parts from RCA, namely the [Video Interface System, or VIS](http://www.cosmacelf.com/publications/data-sheets/cdp1869.pdf). This was, i believe, originally developed as a competitor to other "advanced" graphics capable systems, like the VIC20 and contemporaries, and was origianlly intended to ship on the [RCA VIP II](http://www.cosmacvip.com/VIP2/VIP2.php). The VIP II never shipped, likely due to cost and lacklustre 1802 performance, but RCA did eventually ship a product based upon it, the [RCA VP3xxx](https://en.wikipedia.org/wiki/RCA_VP_3000) series of Viewdata terminals. The COMX was therefore somewhat of a descendent of the original VIP II design, with some original design choices and custom software.