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Steve Russell <> wrote: [...] > A related problem that confuses both HC-16 and HC-12 users when bringing up > a new board is getting the on-chip clock stable. Especially in designs > that use a crystal and the on-chip PLL, this is a challenge anyway. In my experience, especially _with_ te PLL it's no problem. The only problem is IMHO to understand the component selection and configuration, which could be simplified with a better documentation. > When the MCU clock is even slightly unstable, the MCU will react by > executing instructions incorrectly or not at all. This usually produces The only situation when I oberved such behaviour was a D60A _without_ PLL during EMC test with EFT and (indirect) ESD. Seemingly the high impedance, low level EXTAL pin was influenced. And since there is only a /2 division ratio between EXTAL and E clock, it's not too surprising. But I guess that under these circumstances, the clock was not "slightly unstable" - likely the pulse duration was reduced beyond the minimum limit. With the PLL, transients don't affect the XFC voltage noticeable, and therefore even with several wrong EXTAL clock cycles, the E clock doesn't change very much. Especially true with a low PLL bandwidth (large capacitors). > The MORALS: > > Recognize that crystal and PLL problems are layout and component sensitive, the layout of the PLL filtering network is not too critical, is it? > and use careful design and board layout, and good lab technique when > bringing the board up. Ack. And people should try to learn how a crystal oscillator works and how to verify a correct design or ask someone at least when starting volume production. And the board designer should know which currents take which path... > If at all possible, arrange to separate the commissioning of the BDM > connection and debugger from the debugging of the crystal and PLL hardware > details. > > (Perhaps use an external clock source to for initial testing of the BDM and > the MCU functioning before attempting to get the crystal working. Make Correct, that's very useful for a painless start. Oliver -- Oliver Betz, Muenchen |
new BDM multilink
Started by ●May 12, 2004
Reply by ●May 14, 20042004-05-14
Reply by ●May 14, 20042004-05-14
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Dear Mark,
Thanks for replying. I have answered most of the points already. A while back
you allowed me to trial a beta of P&E's ICD12 with high level support.
I have already comment on that, it was a useful comparison with Cosmic Zap. I
have also tried NoICE and generally find Zap the nicest to work with, and more
tolerant to clock fluctuations - I guess it does not display any warning unless
a fluctuation prevents it carrying out a command? There is a strangeness with both the NoICE and Zap, but not the ICD12, and unsecure 12 that the former at times will not connect, until they are closed and unsecure12 is run. This is as if there is an extra configuration of the BDM cable that ICD12, and unsecure 12 does that NoICE and Zap does not do. It is possible that my target is unduly noisy because I've also found that one make of SRAM does not work in one case whereas another make does in the other case. The oscillator and pll look good and clean - I know probing crystals with an oscilloscope can be misleading. Offlist I found the P&E BDM cable for HC16 wonderful some years ago - It seemed to work with the pll set any where even well outside the spec. It is as good as an emulator - whatever Noral say to put down BDM. That was 5 years ago and I think ICD12 which looks the same now looks old and cluttered - hope that comment is useful to you? I have an issue with XP Pro which is resolved by running in it in safemode, and whilst in safemode running Zap on consequently Mulitlink12. After running in safemode etc. then restarting normally the problem is resolved. The problem is that the mouse bounces about all over the screen, this is the case with mouse drive changed, using a usb mouse instead, and uninstalling most everything and progressively reinstalling it. The problem has only arrisen a month after software was reinstall and had until now been running reliably. Thanks once again Andrew Lohmann AIIE Design Engineer PLEASE NOTE NEW EMAIL ADDRESS IS: Bellingham + Stanley Ltd. Longfield Road, Tunbridge Wells, Kent, TN2 3EY, England. Tel: +44 (0) 1892 500400 Fax: +44 (0) 1892 543115 Website: www.bs-ltd.com |
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Reply by ●May 14, 20042004-05-14
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Hi all, why don't you take a look to inDART-HCS12? It is a full-featured BDM real-time programmer/debugger for all the Motorola HCS12 family. It is able to maintain the communication with the target at any frequency in these two ways: 1. Automatic Frequency and BDM4 Version Detection. If the device is new enough to support the BDM4 version, inDART-HCS12 uses both SYNC and ACK commands to synchronize the communication. 2. ECLK Frequency Synchronization. All the BDM commands are ever synchronized, also during CPU frequency changes. Here is the link to the SofTec Microsystems web page: http://www.softecmicro.com/products.html?typeail&title=inDART- HCS12%2FD Regards, Nicola --- In , "Andrew Lohmann's New Email Server" <andrew.lohmann@b...> wrote: > Dear Mark, > Thanks for replying. I have answered most of the points already. A while back you allowed me to trial a beta of P&E's ICD12 with high level support. I have already comment on that, it was a useful comparison with Cosmic Zap. I have also tried NoICE and generally find Zap the nicest to work with, and more tolerant to clock fluctuations - I guess it does not display any warning unless a fluctuation prevents it carrying out a command? > > There is a strangeness with both the NoICE and Zap, but not the ICD12, and unsecure 12 that the former at times will not connect, until they are closed and unsecure12 is run. This is as if there is an extra configuration of the BDM cable that ICD12, and unsecure 12 does that NoICE and Zap does not do. It is possible that my target is unduly noisy because I've also found that one make of SRAM does not work in one case whereas another make does in the other case. The oscillator and pll look good and clean - I know probing crystals with an oscilloscope can be misleading. > > Offlist I found the P&E BDM cable for HC16 wonderful some years ago - It seemed to work with the pll set any where even well outside the spec. It is as good as an emulator - whatever Noral say to put down BDM. That was 5 years ago and I think ICD12 which looks the same now looks old and cluttered - hope that comment is useful to you? > > I have an issue with XP Pro which is resolved by running in it in safemode, and whilst in safemode running Zap on consequently Mulitlink12. After running in safemode etc. then restarting normally the problem is resolved. The problem is that the mouse bounces about all over the screen, this is the case with mouse drive changed, using a usb mouse instead, and uninstalling most everything and progressively reinstalling it. The problem has only arrisen a month after software was reinstall and had until now been running reliably. > > > Thanks once again > Andrew Lohmann AIIE > Design Engineer > > PLEASE NOTE NEW EMAIL ADDRESS IS: > andrew.lohmann@b... > > Bellingham + Stanley Ltd. > Longfield Road, Tunbridge Wells, Kent, TN2 3EY, England. > Tel: +44 (0) 1892 500400 > Fax: +44 (0) 1892 543115 > Website: www.bs-ltd.com > > |
