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Discussion Groups | 68HC12 | How many timer on MC9S12 ?
Join our technical discussions about Freescale Microcontrollers: M68HC12. (Freescale Semiconductor is a Subsidiary of Motorola).
How many timer on MC9S12 ? - David BRUN - May 14 11:35:00 2005
Hello
I'm a HC908 user and I'm looking for S08 or S12 series.
To make choice, I check timer number on board.
I can find "8 channels" on the 9S12A128 datasheet.
What that mean ?
1 timer whith 8 channels or 8 independent timers whith independent
input compare and output compare ?
Thank you very much in advance
David
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
I'm a HC908 user and I'm looking for S08 or S12 series.
To make choice, I check timer number on board.
I can find "8 channels" on the 9S12A128 datasheet.
What that mean ?
1 timer whith 8 channels or 8 independent timers whith independent
input compare and output compare ?
Thank you very much in advance
David
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
How many timer on MC9S12 ? - David BRUN - May 14 11:40:00 2005
Hello
I'm a HC908 user and I'm looking for S08 or S12 series.
To make choice, I check timer number on board.
I can find "8 channels" on the 9S12A128 datasheet.
What that mean ?
1 timer whith 8 channels or 8 independent timers whith independent
input compare and output compare ?
Thank you very much in advance
David
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
I'm a HC908 user and I'm looking for S08 or S12 series.
To make choice, I check timer number on board.
I can find "8 channels" on the 9S12A128 datasheet.
What that mean ?
1 timer whith 8 channels or 8 independent timers whith independent
input compare and output compare ?
Thank you very much in advance
David
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
Re: How many timer on MC9S12 ? - Author Unknown - May 14 13:13:00 2005
Its one timer with 8 ic/oc channels.
Jim
www.freegeeks.net
----- Original Message -----
From: David BRUN
To: 68HC12@68HC...
Sent: Saturday, May 14, 2005 4:40 PM
Subject: [68HC12] How many timer on MC9S12 ? Hello
I'm a HC908 user and I'm looking for S08 or S12 series.
To make choice, I check timer number on board.
I can find "8 channels" on the 9S12A128 datasheet.
What that mean ?
1 timer whith 8 channels or 8 independent timers whith independent
input compare and output compare ?
Thank you very much in advance
David ------------------------------------------------------------------------------
Yahoo! Groups Links
a.. To
[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 )
Jim
www.freegeeks.net
----- Original Message -----
From: David BRUN
To: 68HC12@68HC...
Sent: Saturday, May 14, 2005 4:40 PM
Subject: [68HC12] How many timer on MC9S12 ? Hello
I'm a HC908 user and I'm looking for S08 or S12 series.
To make choice, I check timer number on board.
I can find "8 channels" on the 9S12A128 datasheet.
What that mean ?
1 timer whith 8 channels or 8 independent timers whith independent
input compare and output compare ?
Thank you very much in advance
David ------------------------------------------------------------------------------
Yahoo! Groups Links
a.. To
[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: Re: How many timer on MC9S12 ? - Author Unknown - May 15 5:11:00 2005
Having a single timer limits your dynamic range, multiple timers could have differenet
prescaler values.
Best Regards
Jim
www.freegeeks.net
----- Original Message -----
From: David BRUN
To: 68HC12@68HC...
Sent: Saturday, May 14, 2005 9:36 PM
Subject: [68HC12] Re: How many timer on MC9S12 ? Thank you
I'm reading "S12ECT16B8CV1.pdf", the HCS12 timer guide downloaded on
freescale web site and I don't understand.
The guide says that all channels are independent; we can do every thing.
If we imagine a HCS12 with 8 independent timer, what advantage has it in
front of HCS12A128 with 1 timer and 8 channels?
Which limits impose the common timer on channels work ?
You help me very much
David
--- In 68HC12@68HC..., <jimstuart@f...> wrote:
> Its one timer with 8 ic/oc channels.
> Jim
> www.freegeeks.net
> ----- Original Message -----
> From: David BRUN
> To: 68HC12@68HC...
> Sent: Saturday, May 14, 2005 4:40 PM
> Subject: [68HC12] How many timer on MC9S12 ? > Hello
> I'm a HC908 user and I'm looking for S08 or S12 series.
> To make choice, I check timer number on board.
> I can find "8 channels" on the 9S12A128 datasheet.
> What that mean ?
> 1 timer whith 8 channels or 8 independent timers whith independent
> input compare and output compare ?
> Thank you very much in advance
> David >
----------------------------------------------------------------------------
--
> Yahoo! Groups Links
> a.. To >
> [Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
------------------------------------------------------------------------------
Yahoo! Groups Links
a.. To
[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 )
Best Regards
Jim
www.freegeeks.net
----- Original Message -----
From: David BRUN
To: 68HC12@68HC...
Sent: Saturday, May 14, 2005 9:36 PM
Subject: [68HC12] Re: How many timer on MC9S12 ? Thank you
I'm reading "S12ECT16B8CV1.pdf", the HCS12 timer guide downloaded on
freescale web site and I don't understand.
The guide says that all channels are independent; we can do every thing.
If we imagine a HCS12 with 8 independent timer, what advantage has it in
front of HCS12A128 with 1 timer and 8 channels?
Which limits impose the common timer on channels work ?
You help me very much
David
--- In 68HC12@68HC..., <jimstuart@f...> wrote:
> Its one timer with 8 ic/oc channels.
> Jim
> www.freegeeks.net
> ----- Original Message -----
> From: David BRUN
> To: 68HC12@68HC...
> Sent: Saturday, May 14, 2005 4:40 PM
> Subject: [68HC12] How many timer on MC9S12 ? > Hello
> I'm a HC908 user and I'm looking for S08 or S12 series.
> To make choice, I check timer number on board.
> I can find "8 channels" on the 9S12A128 datasheet.
> What that mean ?
> 1 timer whith 8 channels or 8 independent timers whith independent
> input compare and output compare ?
> Thank you very much in advance
> David >
----------------------------------------------------------------------------
--
> Yahoo! Groups Links
> a.. To >
> [Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
------------------------------------------------------------------------------
Yahoo! Groups Links
a.. To
[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: Re: How many timer on MC9S12 ? - Stephen Trier - May 16 9:42:00 2005
Another drawback to the single 8-channel timer is that you have to
spend CPU cycles on interrupts if you need to generate square waves at
multiple frequencies. In other words, TC7 has the ability to shorten
the timer counter's period below 0xffff, giving you one controllable
frequency without interrupts, but no other channel can do that.
8 single-channel timers could presumably be set to repeat, in hardware,
each at its own rate.
In practice, this isn't often a problem. There are usually plenty of
cycles to spare.
Don't overlook the PWM, too. The only time someone here needed a
programmble frequency output without interrupts, she used the PWM.
It worked fine. She got a four-octave range of musical notes (square
wave output) using 8-bit PWM. I think the full 10.5 octave MIDI gamut
would be possible in 16-bit mode.
Stephen
--
Stephen Trier
Technical Development Lab
Cleveland FES Center
sct@sct@...
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )
spend CPU cycles on interrupts if you need to generate square waves at
multiple frequencies. In other words, TC7 has the ability to shorten
the timer counter's period below 0xffff, giving you one controllable
frequency without interrupts, but no other channel can do that.
8 single-channel timers could presumably be set to repeat, in hardware,
each at its own rate.
In practice, this isn't often a problem. There are usually plenty of
cycles to spare.
Don't overlook the PWM, too. The only time someone here needed a
programmble frequency output without interrupts, she used the PWM.
It worked fine. She got a four-octave range of musical notes (square
wave output) using 8-bit PWM. I think the full 10.5 octave MIDI gamut
would be possible in 16-bit mode.
Stephen
--
Stephen Trier
Technical Development Lab
Cleveland FES Center
sct@sct@...
(You need to be a member of 68hc12 -- send a blank email to 68hc12-subscribe@yahoogroups.com )