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Discussion Groups | 68HC12 | Problem with spi clock
Join our technical discussions about Freescale Microcontrollers: M68HC12. (Freescale Semiconductor is a Subsidiary of Motorola).
Problem with spi clock - Pascal - Jun 4 7:55:47 2007
Hello,
I use 9s12xdpa512. Fbus is 40Mhz. I use spi clock at maximum frequency (spibr=0). In my case the frequency is 20MHz. My card is four plane.
When i put the scope on the sck pin i have this signal (yellow sck pin, blue 5V signal (power))http://www.cijoint.fr/cij42138224615403.jpg
The signal is very bad and i don't understand why. My scope is a 100Mhz.
If i use spi clock at 4 MHz for example the signal looks like good.
What do you think about it?
Tank you for help
Regards
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
I use 9s12xdpa512. Fbus is 40Mhz. I use spi clock at maximum frequency (spibr=0). In my case the frequency is 20MHz. My card is four plane.
When i put the scope on the sck pin i have this signal (yellow sck pin, blue 5V signal (power))http://www.cijoint.fr/cij42138224615403.jpg
The signal is very bad and i don't understand why. My scope is a 100Mhz.
If i use spi clock at 4 MHz for example the signal looks like good.
What do you think about it?
Tank you for help
Regards
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
RE: Problem with spi clock - Darren Moore - Jun 4 8:03:42 2007
Hi Pascal,
At 20Mhz you will have to supply some terminations and impedance
matching, else your going to end up with the overshoot and ringing
as seen on your image.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
>
> Hello,
>
> I use 9s12xdpa512. Fbus is 40Mhz. I use spi clock at maximum
> frequency (spibr=0). In my case the frequency is 20MHz. My
> card is four plane.
> When i put the scope on the sck pin i have this signal
> (yellow sck pin, blue 5V signal
> (power))http://www.cijoint.fr/cij42138224615403.jpg
> The signal is very bad and i don't understand why. My scope
> is a 100Mhz.
> If i use spi clock at 4 MHz for example the signal looks like good.
> What do you think about it?
>
> Tank you for help
>
> Regards
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
Re: Problem with spi clock - Pascal - Jun 4 8:20:34 2007
Hello Daren,
Thank you very much for your help. I don't really understand what you mean. Could you be more precise?
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 2:03 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
At 20Mhz you will have to supply some terminations and impedance
matching, else your going to end up with the overshoot and ringing
as seen on your image.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
>
> Hello,
>
> I use 9s12xdpa512. Fbus is 40Mhz. I use spi clock at maximum
> frequency (spibr=0). In my case the frequency is 20MHz. My
> card is four plane.
> When i put the scope on the sck pin i have this signal
> (yellow sck pin, blue 5V signal
> (power))http://www.cijoint.fr/cij42138224615403.jpg
> The signal is very bad and i don't understand why. My scope
> is a 100Mhz.
> If i use spi clock at 4 MHz for example the signal looks like good.
> What do you think about it?
>
> Tank you for help
>
> Regards
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
Thank you very much for your help. I don't really understand what you mean. Could you be more precise?
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 2:03 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
At 20Mhz you will have to supply some terminations and impedance
matching, else your going to end up with the overshoot and ringing
as seen on your image.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
>
> Hello,
>
> I use 9s12xdpa512. Fbus is 40Mhz. I use spi clock at maximum
> frequency (spibr=0). In my case the frequency is 20MHz. My
> card is four plane.
> When i put the scope on the sck pin i have this signal
> (yellow sck pin, blue 5V signal
> (power))http://www.cijoint.fr/cij42138224615403.jpg
> The signal is very bad and i don't understand why. My scope
> is a 100Mhz.
> If i use spi clock at 4 MHz for example the signal looks like good.
> What do you think about it?
>
> Tank you for help
>
> Regards
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
RE: Problem with spi clock - Darren Moore - Jun 4 9:15:20 2007
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/ but there
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
> On Behalf Of Pascal
> Sent: Monday, 4 June 2007 22:21
> To: 6...@yahoogroups.com
> Subject: Re: [68HC12] Problem with spi clock
> Hello Daren,
>
> Thank you very much for your help. I don't really understand
> what you mean. Could you be more precise?
>
> Regards
>
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
Re: Problem with spi clock - Pascal - Jun 4 9:21:41 2007
Thank you Darren i will try it
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/ but there
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
> On Behalf Of Pascal
> Sent: Monday, 4 June 2007 22:21
> To: 6...@yahoogroups.com
> Subject: Re: [68HC12] Problem with spi clock
>
>
> Hello Daren,
>
> Thank you very much for your help. I don't really understand
> what you mean. Could you be more precise?
>
> Regards
>
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/ but there
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
> On Behalf Of Pascal
> Sent: Monday, 4 June 2007 22:21
> To: 6...@yahoogroups.com
> Subject: Re: [68HC12] Problem with spi clock
>
>
> Hello Daren,
>
> Thank you very much for your help. I don't really understand
> what you mean. Could you be more precise?
>
> Regards
>
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
AW: Problem with spi clock - "Profos, Georg" - Jun 4 9:35:26 2007
I also work with SPI but at lower clock rates. I would be extremely
interested in knowing how you write ISR's fast enough to send and/or
receive data at this speed! At 20Mbit/s, one bytes takes a time of
0.5us, so the ISR may not take longer than that...
Btw, ISR = Interrupt Service Routine
thanks in advance
Georg
________________________________
Von: 6...@yahoogroups.com [mailto:6...@yahoogroups.com] Im Auftrag
von Pascal
Gesendet: Montag, 4. Juni 2007 15:20
An: 6...@yahoogroups.com
Betreff: Re: [68HC12] Problem with spi clock
Thank you Darren i will try it
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com
[mailto:6...@yahoogroups.com ]
> On Behalf Of Pascal
> Sent: Monday, 4 June 2007 22:21
> To: 6...@yahoogroups.com
> Subject: Re: [68HC12] Problem with spi clock
> Hello Daren,
>
> Thank you very much for your help. I don't really understand
> what you mean. Could you be more precise?
>
> Regards
>
[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
interested in knowing how you write ISR's fast enough to send and/or
receive data at this speed! At 20Mbit/s, one bytes takes a time of
0.5us, so the ISR may not take longer than that...
Btw, ISR = Interrupt Service Routine
thanks in advance
Georg
________________________________
Von: 6...@yahoogroups.com [mailto:6...@yahoogroups.com] Im Auftrag
von Pascal
Gesendet: Montag, 4. Juni 2007 15:20
An: 6...@yahoogroups.com
Betreff: Re: [68HC12] Problem with spi clock
Thank you Darren i will try it
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
> -----Original Message-----
> From: 6...@yahoogroups.com
[mailto:6...@yahoogroups.com
> On Behalf Of Pascal
> Sent: Monday, 4 June 2007 22:21
> To: 6...@yahoogroups.com
> Subject: Re: [68HC12] Problem with spi clock
> Hello Daren,
>
> Thank you very much for your help. I don't really understand
> what you mean. Could you be more precise?
>
> Regards
>
[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
Re: Problem with spi clock - Edward Karpicz - Jun 4 10:09:52 2007
Also try enabling "Reduced drive" for clock pin (some RDRx register, RDRS
probably). Thes should help a bit.
Edward
----- Original Message -----
From: "Pascal"
To: <6...@yahoogroups.com>
Sent: Monday, June 04, 2007 4:20 PM
Subject: Re: [68HC12] Problem with spi clock
> Thank you Darren i will try it
>
> Regards
>
> ----- Original Message -----
> From: Darren Moore
> To: 6...@yahoogroups.com
> Sent: Monday, June 04, 2007 3:14 PM
> Subject: RE: [68HC12] Problem with spi clock
>
> Hi Pascal,
>
> google 'transmission lines'
>
> Also a site with lots of information is
> http://www.speedingedge.com/ but there
> are many others.
>
> I simple fix might be to add a 47ohm resistor to the
> spi driver pin, in series with the signal.
>
> Regards,
> Darren
>
> > -----Original Message-----
> > From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
> > On Behalf Of Pascal
> > Sent: Monday, 4 June 2007 22:21
> > To: 6...@yahoogroups.com
> > Subject: Re: [68HC12] Problem with spi clock
> >
> >
> > Hello Daren,
> >
> > Thank you very much for your help. I don't really understand
> > what you mean. Could you be more precise?
> >
> > Regards
> > [Non-text portions of this message have been removed]
> Yahoo! Groups Links
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
probably). Thes should help a bit.
Edward
----- Original Message -----
From: "Pascal"
To: <6...@yahoogroups.com>
Sent: Monday, June 04, 2007 4:20 PM
Subject: Re: [68HC12] Problem with spi clock
> Thank you Darren i will try it
>
> Regards
>
> ----- Original Message -----
> From: Darren Moore
> To: 6...@yahoogroups.com
> Sent: Monday, June 04, 2007 3:14 PM
> Subject: RE: [68HC12] Problem with spi clock
>
> Hi Pascal,
>
> google 'transmission lines'
>
> Also a site with lots of information is
> http://www.speedingedge.com/ but there
> are many others.
>
> I simple fix might be to add a 47ohm resistor to the
> spi driver pin, in series with the signal.
>
> Regards,
> Darren
>
> > -----Original Message-----
> > From: 6...@yahoogroups.com [mailto:6...@yahoogroups.com]
> > On Behalf Of Pascal
> > Sent: Monday, 4 June 2007 22:21
> > To: 6...@yahoogroups.com
> > Subject: Re: [68HC12] Problem with spi clock
> >
> >
> > Hello Daren,
> >
> > Thank you very much for your help. I don't really understand
> > what you mean. Could you be more precise?
> >
> > Regards
> > [Non-text portions of this message have been removed]
> Yahoo! Groups Links
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
RE: Problem with spi clock - jpdi...@free.fr - Jun 4 10:33:03 2007
Hello, Pascal !
I can see that kind of signal... without ground on the scope's probe.
I explain :
- my scope is always connected to the ground, so the static levels are OK, event if I don't have ground cable on my probe.
- When I see that kind of signals, I connect too a short ground cable on the probe of my scope
I think if you connect a resistor of 47 ohms between your probe and the signal you examine, this resistor plus the input capacitance
of your probe acts as a low frequency filter...
I think, "in fine", it would be better to have only one ground for your scope, just the ground of your probe.
Best regards.
Joel Petrique / Diese-Info
-----Message d'origine-----
De : 6...@yahoogroups.com [mailto:6...@yahoogroups.com] De la part de Pascal
Envoyé : lundi 4 juin 2007 15:20
À : 6...@yahoogroups.com
Objet : Re: [68HC12] Problem with spi clock
Thank you Darren i will try it
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/ but there
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
I can see that kind of signal... without ground on the scope's probe.
I explain :
- my scope is always connected to the ground, so the static levels are OK, event if I don't have ground cable on my probe.
- When I see that kind of signals, I connect too a short ground cable on the probe of my scope
I think if you connect a resistor of 47 ohms between your probe and the signal you examine, this resistor plus the input capacitance
of your probe acts as a low frequency filter...
I think, "in fine", it would be better to have only one ground for your scope, just the ground of your probe.
Best regards.
Joel Petrique / Diese-Info
-----Message d'origine-----
De : 6...@yahoogroups.com [mailto:6...@yahoogroups.com] De la part de Pascal
Envoyé : lundi 4 juin 2007 15:20
À : 6...@yahoogroups.com
Objet : Re: [68HC12] Problem with spi clock
Thank you Darren i will try it
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/ but there
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
Re: Problem with spi clock - Pascal - Jun 4 11:37:43 2007
Hello jpdi
I always use only the ground of my probe. This is not cool because at this speed we don't know if the problem comes from the scope or from the hardware :(
Regards
----- Original Message -----
From: j...@free.fr
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 4:34 PM
Subject: RE: [68HC12] Problem with spi clock
Hello, Pascal !
I can see that kind of signal... without ground on the scope's probe.
I explain :
- my scope is always connected to the ground, so the static levels are OK, event if I don't have ground cable on my probe.
- When I see that kind of signals, I connect too a short ground cable on the probe of my scope
I think if you connect a resistor of 47 ohms between your probe and the signal you examine, this resistor plus the input capacitance
of your probe acts as a low frequency filter...
I think, "in fine", it would be better to have only one ground for your scope, just the ground of your probe.
Best regards.
Joel Petrique / Diese-Info
-----Message d'origine-----
De : 6...@yahoogroups.com [mailto:6...@yahoogroups.com] De la part de Pascal
Envoyé : lundi 4 juin 2007 15:20
À : 6...@yahoogroups.com
Objet : Re: [68HC12] Problem with spi clock
Thank you Darren i will try it
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/ but there
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
I always use only the ground of my probe. This is not cool because at this speed we don't know if the problem comes from the scope or from the hardware :(
Regards
----- Original Message -----
From: j...@free.fr
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 4:34 PM
Subject: RE: [68HC12] Problem with spi clock
Hello, Pascal !
I can see that kind of signal... without ground on the scope's probe.
I explain :
- my scope is always connected to the ground, so the static levels are OK, event if I don't have ground cable on my probe.
- When I see that kind of signals, I connect too a short ground cable on the probe of my scope
I think if you connect a resistor of 47 ohms between your probe and the signal you examine, this resistor plus the input capacitance
of your probe acts as a low frequency filter...
I think, "in fine", it would be better to have only one ground for your scope, just the ground of your probe.
Best regards.
Joel Petrique / Diese-Info
-----Message d'origine-----
De : 6...@yahoogroups.com [mailto:6...@yahoogroups.com] De la part de Pascal
Envoyé : lundi 4 juin 2007 15:20
À : 6...@yahoogroups.com
Objet : Re: [68HC12] Problem with spi clock
Thank you Darren i will try it
Regards
----- Original Message -----
From: Darren Moore
To: 6...@yahoogroups.com
Sent: Monday, June 04, 2007 3:14 PM
Subject: RE: [68HC12] Problem with spi clock
Hi Pascal,
google 'transmission lines'
Also a site with lots of information is
http://www.speedingedge.com/ but there
are many others.
I simple fix might be to add a 47ohm resistor to the
spi driver pin, in series with the signal.
Regards,
Darren
[Non-text portions of this message have been removed]
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )