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Groups > comp.arch.embedded > #29511
| Subject | Re: Custom CPU Designs |
|---|---|
| Newsgroups | comp.arch.embedded |
| References | (12 earlier) <d6lmG.14487$Gv6.8602@fx42.am4> <r7eu1d$j6c$1@dont-email.me> <wrB*fISPx@news.chiark.greenend.org.uk> <RsGmG.64714$mk2.26219@fx21.am4> <1d6583ae-457a-4945-97f3-9e9628b0ced6@googlegroups.com> |
| From | Tom Gardner <spamjunk@blueyonder.co.uk> |
| Message-ID | <WAUmG.109550$e1n.85307@fx36.am4> (permalink) |
| Organization | virginmedia.com |
| Date | 2020-04-19 10:11 +0100 |
On 18/04/20 22:53, Rick C wrote: > On Saturday, April 18, 2020 at 1:07:00 PM UTC-4, Tom Gardner wrote: >> On 18/04/20 16:51, Theo wrote: >>> David Brown <david.brown@hesbynett.no> wrote: >>>> The real power comes from when you want to do something that is /not/ >>>> standard, or at least not common. >>>> >>>> Implementing a standard UART in a couple of XMOS cores is a pointless >>>> waste of silicon. Implementing a UART that uses Manchester encoding >>>> for the UART signals so that you can use it on a balanced line without >>>> keeping track of which line is which - /then/ you've got something >>>> that can be done just as easily on an XMOS and is a big pain to do on >>>> a standard microcontroller. >>>> >>>> Implementing an Ethernet MAC on an XMOS is pointless. Implementing an >>>> EtherCAT slave is not going to be much harder for the XMOS than a >>>> normal Ethernet MAC, but is impossible on any microcontroller without >>>> specialised peripherals. >>> >>> The Cypress PSoC has an interesting take on this. You can specify (with >>> the GUI) that you want a component. If you specify a simple component >>> (let's say I2C slave) there's a hard IP for that. But if you specify >>> something that's more complicated (say I2C master and slave on the same >>> pins) it builds it with the existing IP plus some of its FPGA-like logic. >>> Takes more resources but allows you to do many more things than they put >>> in as hard cores. >>> >>> Unfortunately they don't provide a vast quantity of cells for that logic, >>> so it's fine if you want to add just a few unusual bits to the regular >>> microcontroller, but not a big system. (PSoC also has the programmable >>> analogue stuff, which presumably constrains the process they can use) >>> >>> It would be quite interesting to combine that with the XMOS approach - >>> more fluid boundaries between hardware and software. >>> >>> I'm a bit surprised XMOS don't provide 'soft realtime' virtual cores - >>> lock down the cores running a task that absolutely needs to be >>> bounded-latency, and then multitask the remaining tasks across the other >>> cores. If that was provided as an integrated service then it wouldn't >>> need messing about running a scheduler. >> >> What scheduler? >> >> To a very useful approximation the an RTOS's functions are encoded in >> hardware. >> >> The "select" statement is like a "switch" statement, except that the core >> sleeps until one of the "case" conditions becomes true. In effect the case >> conditions are events. Events can be inputs arriving, outputs completing, >> timeouts, etc. > > Isn't that what interrupts are about? Many processors have a "halt and wait > for interrupt" instruction. Hardware on its own is trivial and has been done many times over the decades. XMOS have integrated the hardware with the software with the conceptual tools, and have provided excellent development tools. That has not been achieved elsewhere. >> N.B. as far as a core is concerned, receiving input from a pin is the same >> as receiving a message from another task/core. Ditto output to a pin and >> sending a message to another task/core. Everything is via the "port" >> abstraction, and that extends down into the hardware and i/o system. > > That sounds a lot like the Transputer. Exactly. And xC is a modern successor to Occam, with CSP a core abstraction. Some of the original Transputer team are in XMOS. >> For a short intro to the hardware, software, and concepts see the >> architecture flyer. https://www.xmos.com/file/xcore-architecture-flyer/ >> >> FFI see the XMOS programming guide, which is beautifully written, succinct, >> and clear. https://www.xmos.com/file/xmos-programming-guide/ >> >> I wish all documentation was as good! >> >> >>> After all, there must be applications with a lot of >>> do-this-once-a-second tasks, that would be wasted using a whole core? Do >>> they have a scheduler where you can tell a task to sleep until a >>> particular time? >> >> See "combinable tasks" in my post in response to David Brown's post. >> >> >>> Or is FreeRTOS intended for that? In which case you presumably have to >>> write the code in a different way compared to the hard-tasks? >> >> I really don't see the point of FreeRTOS running inside an xCORE chip. To >> be over simplistic, RTOSs are designed to schedule multiple tasks on a >> single processor and to connect i/o with tasks (typically via interrupts). >> >> All that is done in hardware in the xCORE ecosystem. > > That's true of most processors, no? An I/O event happens and an interrupt > invokes a task called an interrupt handler. > > The tricky part is dealing with the real time requirements of handling the > I/O events. Which task must be done first, which tasks can be interrupted to > deal with other tasks, what resources are required to process an event, etc. > This is what makes real time multitasking difficult. Those problems mostly disappear with sufficient independent cores. What remains is the logical dependencies which can result in livelock or deadlock. No implementation technology can solve those, since they are inherent in either the problem or the architectural solution.
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Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-15 20:51 -0700
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-16 11:59 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-16 13:28 +0200
Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-16 13:10 +0000
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-16 22:16 +0100
Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-16 22:01 +0000
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-16 17:13 -0700
Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-16 18:10 -0700
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 18:37 -0700
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-16 22:08 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 10:02 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-17 10:49 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 15:44 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-17 15:23 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 18:15 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-17 17:49 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-18 15:06 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-18 16:08 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:13 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 14:24 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 16:00 +0200
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-20 14:32 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 23:55 +0100
Re: Custom CPU Designs Reinhardt Behm <rbehm@hushmail.com> - 2020-04-21 15:14 +0800
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-18 16:51 +0100
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-18 18:06 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 14:53 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 10:11 +0100
Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-19 13:19 +0300
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 11:33 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:26 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 14:59 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 13:37 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 22:02 +0100
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-19 22:15 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 15:02 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 02:03 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 14:44 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:20 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 14:57 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 12:38 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 15:58 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 16:27 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 17:36 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 14:02 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 06:15 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 17:25 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 16:56 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 12:42 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 23:16 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 11:10 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 08:09 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 20:07 +0200
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-18 13:09 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-18 21:28 +0100
Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-21 20:29 +0300
Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-21 18:10 +0000
Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-22 09:54 +0300
Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 13:19 +0000
Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-22 18:09 +0300
Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 17:03 +0000
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 11:16 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 10:48 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-18 16:57 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-18 14:21 -0700
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-18 14:50 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 16:32 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 18:12 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 10:09 +0100
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 16:31 +0100
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 16:42 +0100
Re: Custom CPU Designs upsidedown@downunder.com - 2020-04-18 00:43 +0300
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-18 17:07 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 09:11 -0700
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-17 12:17 -0700
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 13:22 -0700
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-17 14:48 -0700
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 15:27 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 16:53 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 17:03 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 19:39 +0200
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 21:25 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 18:27 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 17:58 +0200
Re: Custom CPU Designs Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-04-21 19:41 +0300
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 14:01 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-21 23:21 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-19 20:53 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 14:47 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 02:11 +0100
Re: Custom CPU Designs Paul Rubin <no.email@nospam.invalid> - 2020-04-19 18:31 -0700
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 20:32 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 07:46 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 00:33 -0700
Re: Custom CPU Designs Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-04-20 11:01 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 17:44 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 19:57 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 18:02 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 14:56 -0700
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-17 16:34 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 17:57 +0200
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-21 15:20 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 08:26 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 18:09 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 15:00 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 11:28 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 08:24 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-22 20:18 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 11:45 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-23 17:47 +0200
Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-21 15:35 -0700
Re: Custom CPU Designs Przemek Klosowski <przemek@tux.dot.org> - 2020-04-19 18:52 +0000
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-19 13:42 -0700
Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-20 22:59 +1000
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-20 17:01 -0700
Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-21 10:23 +1000
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-21 03:47 -0700
Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-22 09:26 +1000
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-22 22:06 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-22 14:18 -0700
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-23 22:35 +0100
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 18:20 +0200
Re: Custom CPU Designs Dimiter_Popoff <dp@tgi-sci.com> - 2020-04-22 18:16 +0300
Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 17:06 +0000
Re: Custom CPU Designs Dimiter_Popoff <dp@tgi-sci.com> - 2020-04-22 20:17 +0300
Re: Custom CPU Designs Grant Edwards <invalid@invalid.invalid> - 2020-04-22 17:28 +0000
Re: Custom CPU Designs George Neuner <gneuner2@comcast.net> - 2020-04-23 04:59 -0400
Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-20 17:27 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 17:58 +0200
Re: Custom CPU Designs pault.eg@googlemail.com - 2020-04-21 01:00 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-21 19:21 +0200
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-17 17:18 +0100
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 07:40 -0700
Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-16 12:28 -0700
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 13:50 -0700
Re: Custom CPU Designs jim.brakefield@ieee.org - 2020-04-16 14:19 -0700
Re: Custom CPU Designs Theo <theom+news@chiark.greenend.org.uk> - 2020-04-16 22:33 +0100
Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-17 11:29 +1000
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 18:42 -0700
Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-17 12:35 +1000
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 20:01 -0700
Re: Custom CPU Designs Clifford Heath <no.spam@please.net> - 2020-04-17 14:54 +1000
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-16 23:54 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-17 10:38 +0200
Re: Custom CPU Designs Rick C <gnuarm.deletethisbit@gmail.com> - 2020-04-17 09:13 -0700
Re: Custom CPU Designs David Brown <david.brown@hesbynett.no> - 2020-04-20 18:02 +0200
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