Hi, I'm currently using an Adapt9S12DP256 module for my final year project. I'd like to know if it's possible to overclock it and if it is, what are the details in doing so? Thanks
Overclocking a Freescale 9S12DP256C MCU
Started by ●November 18, 2008
Reply by ●November 18, 20082008-11-18
Mario wrote:> Hi, > > I'm currently using an Adapt9S12DP256 module for my final year > project. I'd like to know if it's possible to overclock it and if it > is, what are the details in doing so?It appears that modern HCS12 can be overclocked by as much 3 x rated clock. The clock is configured by the PLL register settings. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●November 19, 20082008-11-19
Vladimir Vassilevsky wrote:>> I'm currently using an Adapt9S12DP256 module for my final year >> project. I'd like to know if it's possible to overclock it and if it >> is, what are the details in doing so? > >It appears that modern HCS12 can be overclocked by as much 3 x rated >clock. The clock is configured by the PLL register settings.although I'm also rather sure that they can run somewhat faster than 24MHz, do you have any sources, measurements, test suites proving your "x 3" claim? Oliver -- Oliver Betz, Munich despammed.com might be broken, use Reply-To:
Reply by ●November 19, 20082008-11-19
Oliver Betz wrote:> Vladimir Vassilevsky wrote: > > >>>I'm currently using an Adapt9S12DP256 module for my final year >>>project. I'd like to know if it's possible to overclock it and if it >>>is, what are the details in doing so? >> >>It appears that modern HCS12 can be overclocked by as much 3 x rated >>clock. The clock is configured by the PLL register settings. > > > although I'm also rather sure that they can run somewhat faster than > 24MHz, do you have any sources, measurements, test suites proving your > "x 3" claim?Why can't you just try and see for yourself? I have a device with S12D64. I overclocked it just for curiosity. It appeared to be operable up to ~70MHz. Probably the silicon can go even higher; 70MHz is where the internal PLL got stuck. Of course, I didn't check every fine detail of the operation however it seemed to work normally. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●November 20, 20082008-11-20
Vladimir Vassilevsky wrote:>Oliver Betz wrote: >> Vladimir Vassilevsky wrote: >> >>>>I'm currently using an Adapt9S12DP256 module for my final year >>>>project. I'd like to know if it's possible to overclock it and if it >>>>is, what are the details in doing so? >>> >>>It appears that modern HCS12 can be overclocked by as much 3 x rated >>>clock. The clock is configured by the PLL register settings. >> >> although I'm also rather sure that they can run somewhat faster than >> 24MHz, do you have any sources, measurements, test suites proving your >> "x 3" claim? > >Why can't you just try and see for yourself?I _did_ overclock S12 devices when I checked the PLL, but made no thorough tests whether I can _safely use_ the higher frequency. Just wanted to know whether you have better information.>I have a device with S12D64. I overclocked it just for curiosity. It >appeared to be operable up to ~70MHz. Probably the silicon can go even >higher; 70MHz is where the internal PLL got stuck. Of course, I didn't >check every fine detail of the operation however it seemed to work normally.This "test" doesn't IMNSHO justify your statement in your previous posting. You shouldn't state "It appears that modern HCS12 can be overclocked by as much 3 x" if you didn't reasonable tests. Oliver -- Oliver Betz, Munich despammed.com might be broken, use Reply-To:
Reply by ●November 20, 20082008-11-20
On Tue, 18 Nov 2008 14:46:18 -0800 (PST), Mario <mallivy@yahoo.com> wrote:>I'm currently using an Adapt9S12DP256 module for my final year >project. I'd like to know if it's possible to overclock it and if it >is, what are the details in doing so?Why do you want to do this ? Does your software consume so much resources that the CPU is not capable of handling it at the nominal maximum clock frequency ? While overclocking might work in a one off (such as a student) project, you are not going to be able to use this approach in real world professional design jobs. In those situations, you either have to improve your software or use a more efficient processor. Chip manufacturers have to be conservative when specifying the maximum clock frequency so that the chip will work with any operating voltage within the specification and within the whole temperature range for any chip produced at various fabs with slightly different processing. Typically the limiting factor will be the minimum supply voltage and the maximum ambient temperature. Running the chip at the maximum specified operational voltage will typically allow running at a higher clock frequency. However, this will typically increase the power dissipation proportional to the clock frequency and the supply voltage squared, so the junction temperature will also increase. Apart for the direct meltdown, the increase of the junction temperature will decrease the MTBF (Mean Time Before Failure) quite rapidly. To avoid this, you have to limit the maximum allowed ambient temperature or increase the cooling by a large heatsink or forced air cooling. If these are acceptable limitations and especially if you are able to select the best chips from different production lots, you certainly would be able to overclock quite a lot, but you would typically not be able to design a commercially successful product with these limitations. Paul
Reply by ●November 20, 20082008-11-20
On Nov 19, 12:46=A0am, Mario <mall...@yahoo.com> wrote:> Hi, > > I'm currently using an Adapt9S12DP256 module for my final year > project. I'd like to know if it's possible to overclock it and if it > is, what are the details in doing so? > > ThanksThe maximum clock frequency specified is at highest temperature and lowest supply voltage. Freescale are in that busyness not since yesterday so I would be very surprised if there is a lot of reserve to be had over temperature, voltage and of course batch variations. But if you can sacrifice some range of the above - say, this is just a prototype you want to have running faster and not put in production - just try to raise the frequency until it stops working, then settle for say 90 or 95% that and there you are. Didi ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/
Reply by ●November 20, 20082008-11-20
Didi wrote:> The maximum clock frequency specified is at highest temperature > and lowest supply voltage. > Freescale are in that busyness not since yesterday so I would be > very surprised if there is a lot of reserve to be had over > temperature, voltage and of course batch variations.There are also non-technical reasons for the vendors to under rate their chips: marketing, legacy compatibility, export regulations. Motorola is one of the oldest players and this is why modern HCS12s have that much of potential reserve (3 times of speed). The techology improved many times since HCS12 was introduced; there is no advantage in the manufacturing of the initial slow variant.> But if you can sacrifice some range of the above - say, this > is just a prototype you want to have running faster and not > put in production - just try to raise the frequency until it stops > working, then settle for say 90 or 95% that and there you are.Fie, how boring. First of all, overclocking is sport. It is fun :-) Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●November 20, 20082008-11-20
On Nov 18, 5:46=A0pm, Mario <mall...@yahoo.com> wrote:> Hi, > > I'm currently using an Adapt9S12DP256 module for my final year > project. I'd like to know if it's possible to overclock it and if it > is, what are the details in doing so? > > ThanksYes it can be. But one thing to watch would the A/D Convertors. Once you start overclocking them, they lose linearity. And as others have asked, why? Do you need more speed? Do you have tasks not completing within their allowed time? If not, there is no real reason to crank up the clock. Probably not an issue, but in real world EMI/EMC is an issue, and higher clock speeds cause more problems. JW
Reply by ●November 21, 20082008-11-21
Vladimir Vassilevsky wrote:>Didi wrote: > >> The maximum clock frequency specified is at highest temperature >> and lowest supply voltage. >> Freescale are in that busyness not since yesterday so I would be >> very surprised if there is a lot of reserve to be had over >> temperature, voltage and of course batch variations. > >There are also non-technical reasons for the vendors to under rate their >chips: marketing, legacy compatibility, export regulations. > >Motorola is one of the oldest players and this is why modern HCS12s have >that much of potential reserve (3 times of speed). The techology >improved many times since HCS12 was introduced; there is no advantage intell me more - what exactly did they change? Oliver -- Oliver Betz, Munich despammed.com might be broken, use Reply-To:
