> "benn" <benn686@hotmail.com> skrev i meddelandet
> news:33157349-c306-4837-a17c-23a8d245bfa3@u12g2000prd.googlegroups.com...
>
>>I have an atmega16 that interfaces to a motor with a quadrature
>>encoder sensor. Turns out the frequency of the pulses are much more
>>than my little 4Mhz can handle (the micro does other things as well!)
>>As a result, the motor control isn't very accurate, nor does it react
>>very fast.
>>
>>SO.. I'm looking for either a quadrature decoder IC that can take the
>>load off (will calculate position/velocity and interface to a host
>>micro via serial/parallel bus), OR, a beefy microcontroller with built-
>>in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
>>going the microcontroller route.
>>
>
>
> Why not try an XMEGA which has the Quadrature Encoder built in.
Well done Ulf, I said the same thing 8 days ago ;)
An app note is here
http://www.atmel.com/dyn/resources/prod_documents/doc8109.pdf
Any news on the sampling status of the xmega - can the OP
actually get any ?
[Shame they are not 5V parts (nor even 5V tolerant)
- hard to drive Power MOSFETS from a 3v uC ]
They get a tick for the peripherals tho....
-jg
Reply by Ulf Samuelsson●August 7, 20082008-08-07
"benn" <benn686@hotmail.com> skrev i meddelandet
news:33157349-c306-4837-a17c-23a8d245bfa3@u12g2000prd.googlegroups.com...
>I have an atmega16 that interfaces to a motor with a quadrature
> encoder sensor. Turns out the frequency of the pulses are much more
> than my little 4Mhz can handle (the micro does other things as well!)
> As a result, the motor control isn't very accurate, nor does it react
> very fast.
>
> SO.. I'm looking for either a quadrature decoder IC that can take the
> load off (will calculate position/velocity and interface to a host
> micro via serial/parallel bus), OR, a beefy microcontroller with built-
> in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
> going the microcontroller route.
>
Why not try an XMEGA which has the Quadrature Encoder built in.
--
Best Regards,
Ulf Samuelsson
ulf@a-t-m-e-l.com
This message is intended to be my own personal view and it
may or may not be shared by my employer Atmel Nordic AB
Reply by ●August 3, 20082008-08-03
On Jul 30, 7:18=EF=BF=BDam, benn <benn...@hotmail.com> wrote:
> I have an atmega16 that interfaces to a motor with a quadrature
> encoder sensor. =EF=BF=BD Turns out the frequency of the pulses are much =
more
> than my little 4Mhz can handle (the micro does other things as well!)
> As a result, the motor control isn't very accurate, nor does it react
> very fast.
>
> SO.. I'm looking for either a quadrature decoder IC that can take the
> load off (will calculate position/velocity and interface to a host
> micro via serial/parallel bus), OR, a beefy microcontroller with built-
> in decoders (and pwm output). =EF=BF=BD32-bit with lots of GPIO is ideal =
if
> going the microcontroller route.
A seperate chip is a bad idea as their are so many micros with 2 phase
counters built in. There are even several design kits (board and
software) for peanuts around.
Reply by Capoccetta●August 1, 20082008-08-01
On 30 Lug, 08:18, benn <benn...@hotmail.com> wrote:
> SO.. I'm looking for either a quadrature decoder IC that can take the
> load off (will calculate position/velocity and interface to a host
> micro via serial/parallel bus), OR, a beefy microcontroller with built-
> in decoders (and pwm output). =A032-bit with lots of GPIO is ideal if
> going the microcontroller route.
Hi, You could give a look at the HCTL2016 datasheet and then choose
between using the part or implementing it in a PLD (as I did).
>I have an atmega16 that interfaces to a motor with a quadrature
>encoder sensor. Turns out the frequency of the pulses are much more
>than my little 4Mhz can handle (the micro does other things as well!)
>As a result, the motor control isn't very accurate, nor does it react
>very fast.
>
>SO.. I'm looking for either a quadrature decoder IC that can take the
>load off (will calculate position/velocity and interface to a host
>micro via serial/parallel bus), OR, a beefy microcontroller with built-
>in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
>going the microcontroller route.
I had exactly the same problem a while ago - the quadrature output was
much faster than my micro could keep up with (even if it wasn't doing
anything else!).
I successfully used the Agilent (now Avago) HCTL-2022 decoder chip.
Very fast & accurate and no "gotchas" (from memory - ymmv).
Here's the URL for the datasheet - good luck.
http://www.avagotech.com/assets/downloadDocument.do?id=1780&Source=SearchResultPage
>I have an atmega16 that interfaces to a motor with a quadrature
>encoder sensor. Turns out the frequency of the pulses are much more
>than my little 4Mhz can handle (the micro does other things as well!)
>As a result, the motor control isn't very accurate, nor does it react
>very fast.
>
>SO.. I'm looking for either a quadrature decoder IC that can take the
>load off (will calculate position/velocity and interface to a host
>micro via serial/parallel bus), OR, a beefy microcontroller with built-
>in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
>going the microcontroller route.
Luminary, dsPIC and other chips have QEI interfaces. The Luminary ones
have some extra features for speed measurement, IIRC.
Many DSPs have them as well... motor control is one of those crossover
areas. LSI makes some stand-alone counter chips, or you could use a
CPLD or FPGA.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by Monte Dalrymple●July 30, 20082008-07-30
You might look at: http://www.rabbit.com/products/rio/
"benn" <benn686@hotmail.com> wrote in message
news:33157349-c306-4837-a17c-23a8d245bfa3@u12g2000prd.googlegroups.com...
>I have an atmega16 that interfaces to a motor with a quadrature
> encoder sensor. Turns out the frequency of the pulses are much more
> than my little 4Mhz can handle (the micro does other things as well!)
> As a result, the motor control isn't very accurate, nor does it react
> very fast.
>
> SO.. I'm looking for either a quadrature decoder IC that can take the
> load off (will calculate position/velocity and interface to a host
> micro via serial/parallel bus), OR, a beefy microcontroller with built-
> in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
> going the microcontroller route.
>
Reply by Den●July 30, 20082008-07-30
"benn" <benn686@hotmail.com> wrote in message
news:33157349-c306-4837-a17c-23a8d245bfa3@u12g2000prd.googlegroups.com...
>I have an atmega16 that interfaces to a motor with a quadrature
> encoder sensor. Turns out the frequency of the pulses are much more
> than my little 4Mhz can handle (the micro does other things as well!)
> As a result, the motor control isn't very accurate, nor does it react
> very fast.
>
> SO.. I'm looking for either a quadrature decoder IC that can take the
> load off (will calculate position/velocity and interface to a host
> micro via serial/parallel bus), OR, a beefy microcontroller with built-
> in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
> going the microcontroller route.
>
> I have an atmega16 that interfaces to a motor with a quadrature
> encoder sensor. Turns out the frequency of the pulses are much more
> than my little 4Mhz can handle (the micro does other things as well!)
> As a result, the motor control isn't very accurate, nor does it react
> very fast.
>
> SO.. I'm looking for either a quadrature decoder IC that can take the
> load off (will calculate position/velocity and interface to a host
> micro via serial/parallel bus), OR, a beefy microcontroller with built-
> in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
> going the microcontroller route.
>
>I have an atmega16 that interfaces to a motor with a quadrature
>encoder sensor. Turns out the frequency of the pulses are much more
>than my little 4Mhz can handle (the micro does other things as well!)
>As a result, the motor control isn't very accurate, nor does it react
>very fast.
You haven't mentioned much about your situation, such as the motor's
rate, the number of A/B transitions per revolution, etc. You might be
okay with what you have, but just need to think more closely about the
details to make it work cleanly. Hard to do anything more than accept
your conclusion, though, without more info.
>SO.. I'm looking for either a quadrature decoder IC that can take the
>load off (will calculate position/velocity and interface to a host
>micro via serial/parallel bus), OR, a beefy microcontroller with built-
>in decoders (and pwm output). 32-bit with lots of GPIO is ideal if
>going the microcontroller route.
There is (or was) an expensive HP part that I've used in the past, as
well, the HCTL-2020. It is designed for the purpose and works well,
but you pay for it when you find it. A separate micro would be
cheaper, I think, but you've have to code it up. I'll leave the
do-all micro recommendations to others.
Jon
P.S. I've handled motors running at 250 RPM (actually, I controlled
the motor speed, too, and 250 RPM was the max), coupled to optical
encoders with 10000 A/B transitions per rotation (medical pumps.)
There is a cam attatched to the motor, so there was also analog
conversion of that and a real time graphics display set up to display
the home and certain key pulses other than A and B, along with the cam
height, so that the workman could adjust the optical encoder relative
to the cam shaft to calibrate the motor while spinning (requirement.)
I mapped the timing in a hand-drawn paper diagram before attempting
the coding. By the time I was writing code (and I did use assembly
for some critical parts of it), I'd already resolved the mechanism to
use and knew it was sufficient.