jhuang@ccnysci.UUCP (Jian Huang) (04/17/89)
I was very glad to find this group because I play m6809
almost every day. We use it in our complicated step motor
contoller. This group will give me a lots help.
Recently we try to improve the system performance without
hardware modification. One way is using higher system
clock. MC68b09 can only run at 2 mhz. Is there any fast
version available? We ran that chip at 3 mhz wihtout any
problem. But I don't know the long-term effect to the
system. Does anyone have such experience on this?
--
~~~~~~~~~~~~~~~~~~ JIAN HUANG ~~~~~~~~~~~~~~~~~~~~~
| 611 W.137 St. Apt.61, New York, NY 10031 |
~~~~~~~ (212) 690-4561(H) (212) 690-6866(O) ~~~~~~~baxter@madeleine.ics.uci.edu (Ira Baxter) (04/17/89)
My understanding is that Hitachi offers a 3Mhz 6809 part. I never did understand why much faster parts are not made... surely the manufacturer's process technologies are up to it (look at the 68K speeds!). -- Ira Baxter
lnewman@emdeng.Dayton.NCR.COM (Lee.A.Newman) (04/17/89)
In article <12160@paris.ics.uci.edu> Ira Baxter <baxter@madeleine.ics.uci.edu> writes: >My understanding is that Hitachi offers a 3Mhz 6809 part. I never >did understand why much faster parts are not made... surely the >manufacturer's process technologies are up to it (look at the >68K speeds!). Two points: 1) Speeds of other processors usually are their 'clock speeds', where the 6809's speed is its 'bus speed'. What does this mean? Since other processors are microcoded, it takes several clock cycles to accomplish the same thing the 6809 does in one bus cycle. An example: a 68000 takes four of its 'clock cycles' to fetch or store one piece of data from memory. Each such fetch or store is a 'bus cycle'. A 68020 uses three clock cycles per bus cycle. Intel processors have similar numbers. A 6809, on the other hand, counts in 'bus cycles'. So, a 2 MHz 6809 has as many bus cycles per unit time as an 8 MHz 68000, or a 68020 running at 6 MHz. 2) Motorola processors (NOT Hitachi!) have been notorious for running at much higher clock speeds than what their data sheets say. Two cases in point: The Radio Shack Color Computer (Coco) routinely ran at 1.78 MHz when the part Tandy was buying was the 1 MHz part. A few machines, though, did have trouble. I personally obtained one of the first 68020's available without a non- disclosure agreement. At that time, Motorola was only selling 12 MHz parts, but their data sheets also listed 16 MHz specs. The Motorola rep. who I talked to said that I could run these parts at 16 MHz, as long as I kept them cool enough. Obviously, Motorola would not guarantee proper operation, but, you'se takes your's chances. Also, just because the part would run with a higher crystal does not mean that all other propagation delays are better than the data sheet for the part you bought. So, in Conclusion, a two MHz 6809 is not as slow as it sounds, and you can probably increase the clock speed of the processor, as long as you take pains to insure that your processor does not get too hot. Enjoy! Lee Newman lnewman@emdeng.dayton.NCR.com
mdg@macs.UUCP (Mark Griffith) (04/20/89)
In article <1605@ccnysci.UUCP>, jhuang@ccnysci.UUCP (Jian Huang) writes: > > I was very glad to find this group because I play m6809 > almost every day. We use it in our complicated step motor > contoller. This group will give me a lots help. > Recently we try to improve the system performance without > hardware modification. One way is using higher system > clock. MC68b09 can only run at 2 mhz. Is there any fast > version available? We ran that chip at 3 mhz wihtout any > problem. But I don't know the long-term effect to the > system. Does anyone have such experience on this? Hitachi makes a 3Mhz version of the 6809, but for the life of me, I can't remember their part number for it. Call you local Hitachi office and ask them. I understand it is a CMOS version certified for 3Mhz, but has been run at 4Mhz without problems. Mark UUCP: mdg@macs BITNET: GRIFFITH@STETSON
jhallen@wpi.wpi.edu (Joseph H Allen) (04/21/89)
In article <1605@ccnysci.UUCP> jhuang@ccnysci.UUCP (Jian Huang) writes: > >version available? We ran that chip at 3 mhz wihtout any >problem. But I don't know the long-term effect to the >system. Does anyone have such experience on this? I think it's safe for the processor to do this (you have to go quite fast for the processor itself to start screwing up (I've seen 1Mhz parts run at 2Mhz)). But, take a look at the bus timing: The set-up and hold times remain the same no matter what speed the processor is running at. So if you increase the processor speed, the peripheral access time must be much faster than if you used a higher speed part at that same speed.
easton@aucis.UUCP (Jeff Easton) (05/02/89)
In article <1984@wpi.wpi.edu>, jhallen@wpi.wpi.edu (Joseph H Allen) writes: > In article <1605@ccnysci.UUCP> jhuang@ccnysci.UUCP (Jian Huang) writes: > > > >version available? We ran that chip at 3 mhz wihtout any > >problem. But I don't know the long-term effect to the > >system. Does anyone have such experience on this? > > I think it's safe for the processor to do this (you have to go quite fast for > the processor itself to start screwing up (I've seen 1Mhz parts run at 2Mhz)). > But, take a look at the bus timing: The set-up and hold times remain the > same no matter what speed the processor is running at. So if you increase the > processor speed, the peripheral access time must be much faster than if you > used a higher speed part at that same speed. Whoa! hold the phone! Remember that that 2 Mhz 68B09 is the *exact* same part as that 1 Mhz 6809. The only difference is that the 68B09 has been tested for a 2 Mhz speed and has been rated to run at said speed. The setup and hold times of the 1 Mhz part are spec'ed assuming that the main clock is indeed running at 1 Mhz. If you take that 1 Mhz part and run it at 2 Mhz (and it manages to run at that speed) then your effective setup and hold times are the same as the 2 Mhz part. Mind you, Motorola wont guarantee that that 1 Mhz part will meet the 2 Mhz spec's, after all, thats why they sell a 2 Mhz version. They guarantee that their 2 Mhz version will meet their published spec's. Moral of this story, The 2 Mhz chip is the same die as the 1 Mhz version, its just been tested and guaranteed to work reliably at 2 Mhz. You can proably take a 1 Mhz part and run it at 6 Mhz. You would proably need a heatsink on the chip and even then, all the other peripherals proably wouldn't keep up with it. Notice that I have never tried the above, I only think it would be neat to try. In college someone once boasted that they took a SWTP 6800 machine up to 12 Mhz before it quit. The first part to die was a 6850 ACIA. -Later Jeff Easton Zenith Data Systems OS-9 on a 6 Mhz 6809 system would be awsome. :>
jhallen@wpi.wpi.edu (Joseph H Allen) (05/03/89)
In article <410@aucis.UUCP> easton@aucis.UUCP (Jeff Easton) writes: [ -stuff- deleted ] > Moral of this story, The 2 Mhz chip is the same die as the 1 Mhz >version, its just been tested and guaranteed to work reliably at >2 Mhz. You can proably take a 1 Mhz part and run it at 6 Mhz. You would >proably need a heatsink on the chip and even then, all the other peripherals >proably wouldn't keep up with it. > > Notice that I have never tried the above, I only think it would be neat >to try. In college someone once boasted that they took a SWTP 6800 machine >up to 12 Mhz before it quit. The first part to die was a 6850 ACIA. Another neat thing to do is try to see how slow the chips will run: 6800 and 6809 have a minimum clock speed because they use DRAMs for the registers. How many seconds can you hold up the clock.... (actually there are even some applications for this: if you want the CPU to be synchronized to a video system and you do it by stopping the clock during verticle or horz blanking, or if you only want to processor to run only during the blanking...) Ps: 6809 and OS9 should have become the standard PC, not the IBM PC (we were robbed...)
jonh@tekgen.BV.TEK.COM (Jon Howell) (05/05/89)
>> >version available? We ran that chip at 3 mhz wihtout any >> >problem. But I don't know the long-term effect to the >> >system. Does anyone have such experience on this? >> >> I think it's safe for the processor to do this (you have to go quite fast for > >Whoa! hold the phone! > > Notice that I have never tried the above, I only think it would be neat >to try. In college someone once boasted that they took a SWTP 6800 machine >up to 12 Mhz before it quit. The first part to die was a 6850 ACIA. > >OS-9 on a 6 Mhz 6809 system would be awsome. :> Whoa! hold the fax! :-) Just imagine--take one of those Intel 386s and pump it up a tad--we could use FM bands as modem channels--without an FM tuner! :-) "Yeeeep, I got a little ol' 300MHz board.." :-) And then, in the history books: "The first computers occupied a room and had to be kept cool with expensive air conditioners. Later computers ran at room tempurature in thumbnail size boxes. Today, four hundred of yesterday's computers would fit on the head of a pin, but each one has a heat sink roughly the size of a 747." (-: Just a humorous little interlude. :-) --Jon -- jonh@tekgen.bv.tek.com (503) MAK-SEMA Jon Howell | Q: How come they never // // // _ __ _ . . . . ___ . _ | play that on the radio? // // // / \(_ __ (_) |\/| /| |\ | | /| / | A: They should. // // // \_/__) / | | /"| | \| _|_ /"| \_ | --Dave Barry
easton@aucis.UUCP (Jeff Easton) (05/07/89)
In article <2171@wpi.wpi.edu>, jhallen@wpi.wpi.edu (Joseph H Allen) writes: > In article <410@aucis.UUCP> easton@aucis.UUCP (Jeff Easton) writes: > > 6809 have a minimum clock speed because they use DRAMs for the registers. How > many seconds can you hold up the clock.... (actually there are even some > applications for this: if you want the CPU to be synchronized to a video > system and you do it by stopping the clock during verticle or horz blanking, > or if you only want to processor to run only during the blanking...) > > Ps: 6809 and OS9 should have become the standard PC, not the IBM PC (we were > robbed...) Obviously the best way to set up a 6809 video system is to interleave the 6809 with the CRTC thereby enabling the 6809 to run all the time. If thats not possible, the next best way to stop the CPU is with the /HALT line. This will tristate the CPU busses and wait indefinitely without loss of data. The crystal clock is still running thereby maintaning the dynamic registers contents. Note that the Hitachi 6309 is not a "static" CMOS design. It suffers from the same problem as the NMOS version. When Intel commisioned the CMOS version of the 80286 they specified it as a static part so that laptop makers could turn off the clocks during nonuse, thereby reducing battery power further. I dont believe any of the major laptop makers used this feature tho... Jeff Easton Zenith Data Systems UUCP: !mailrus!sharkey!aucis!easton