how is the BS2p faster than the BS2sx??
Archiver
Posts: 46,084
hello,
the parallax web site seems to say that the bs2p is 20percent
faster than the bs2sx
am I missreading this or what is the explanation?
thanks
the parallax web site seems to say that the bs2p is 20percent
faster than the bs2sx
am I missreading this or what is the explanation?
thanks
Comments
support to explain the
turbo mode).
The BS2p24 is indeed faster than the BS2sx.
The processor speed of the BS2p24 (and BS2p40) is a 20 MHz Turbo, enabling it to
run at program
execution speed of ~12,000 instructions/second compared to ~10,000
instructions/second on the BS2sx.
Comparatively speaking, the BS2p24 and BS2p40 are approximately 20% faster than
the BS2sx and 3
times faster than the BS2.
Turbo Mode
The SX chip can run in compatible mode (4 clock cycles per instruction) OR
The SX chip can run in turbo mode (approximately 1 clock cycle per instruction)
Parallax pre-programs the SX48 chip for the turbo mode with the BS2p and BS2p40.
The turbo mode affects the clock rate so the firmware needed to be modified
(from the BS2) to
accommodate for the timing changes.
I hope this is more helpful than confusing....
Erik Wood
Parallax, Inc.
599 Menlo Dr., Suite #100
Rocklin, CA 95765
(916) 624-8333
www.parallaxinc.com
Original Message
From: rad0 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=YpMX-kw7SjOiNKdrDz4wksKKMogaeDe2xDxrVr9Ydemh_5a3RhDwc4HtFMSxVlK8O3aOEr6iVsl3]rad0@a...[/url
Sent: Friday, November 15, 2002 5:48 AM
To: stampers!
Subject: [noparse][[/noparse]basicstamps] how is the BS2p faster than the BS2sx??
hello,
the parallax web site seems to say that the bs2p is 20percent
faster than the bs2sx
am I missreading this or what is the explanation?
thanks
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and Body
of the message will
be ignored.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
[noparse][[/noparse]Non-text portions of this message have been removed]
I noticed in the manual for the time per pulse on a pulsout,
it is 1.18 us (bs2p); versus .8 us for a bs2sx
so is the bs2p not in turbo mode for this measurement or
if yes, this seems slower to me...
just curious, thanks
Original Message
From: "Erik Wood" <ewood@p...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, November 15, 2002 9:42 AM
Subject: RE: [noparse][[/noparse]basicstamps] how is the BS2p faster than the BS2sx??
> I'll try my best to answer this one (with the assistance of Stephen in
tech. support to explain the
> turbo mode).
>
> The BS2p24 is indeed faster than the BS2sx.
>
> The processor speed of the BS2p24 (and BS2p40) is a 20 MHz Turbo, enabling
it to run at program
> execution speed of ~12,000 instructions/second compared to ~10,000
instructions/second on the BS2sx.
> Comparatively speaking, the BS2p24 and BS2p40 are approximately 20% faster
than the BS2sx and 3
> times faster than the BS2.
>
> Turbo Mode
>
> The SX chip can run in compatible mode (4 clock cycles per instruction) OR
> The SX chip can run in turbo mode (approximately 1 clock cycle per
instruction)
>
> Parallax pre-programs the SX48 chip for the turbo mode with the BS2p and
BS2p40.
> The turbo mode affects the clock rate so the firmware needed to be
modified (from the BS2) to
> accommodate for the timing changes.
>
> I hope this is more helpful than confusing....
>
> Erik Wood
>
> Parallax, Inc.
> 599 Menlo Dr., Suite #100
> Rocklin, CA 95765
> (916) 624-8333
> www.parallaxinc.com
>
>
Original Message
> From: rad0 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=r4e414BEZKvt6fRACieFA_ix8EeIYZLKgDSh17yMmMFDFnRiksbPh4dNPlsZ5Pdt05Y1k8yo92yN]rad0@a...[/url
> Sent: Friday, November 15, 2002 5:48 AM
> To: stampers!
> Subject: [noparse][[/noparse]basicstamps] how is the BS2p faster than the BS2sx??
>
>
> hello,
>
> the parallax web site seems to say that the bs2p is 20percent
> faster than the bs2sx
>
> am I missreading this or what is the explanation?
>
>
> thanks
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will
> be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
The BS2p is running in turbo mode, a capability of the SX48 Ubicon
chip that allows it to pipeline instructions for every single clock
cycle, instead of one instruction for every four clock cycles.
The BS2sx runs with a 50 mhz clock, but executes instructions slower
than the BS2p with its 20 mhz clock, because of turbo mode. While
the BS2sx and BS2e too have Ubicon SX28 processors, capable of turbo
mode, those chips run in "compatibility mode" with the old 4 clock
cycles per instruction. There may have been an issue with rewriting
the interpreter for the SX28.
You might think that the BS2p would run faster than the BS2sx in the
ratio of 4*20/50 = 80/50. That would on the surface of it be 60%
faster! But I guess there are some other things going on to make it
work.
Things like PAUSE take the same time no matter what, while
instructions like PULSIN have individual timings that you have to be
aware of:
BS2p BS2sx BS2,BS2e
pulsin: 0.75us vs 0.8us vs 2us resolution
pulsout: 1.18us vs 0.8us vs 2us
rctime: 0.9us vs 0.8us vs 2us
count: 287us vs 400us vs 1ms
There are also differences in the timing parameters in other commands
like freqout and serout. These timings are not in any simple ratio
that I can see.
You can actually measure the time differences for execution of
individual instructions like,
HIGH pin:
BS2p BS2sx BS2,BS2e
41 us 56 us 140 us
So the speed increase for that particular instruction is about 36%
from the 'sx to the 'p.
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
>hello,
>
>the parallax web site seems to say that the bs2p is 20percent
>faster than the bs2sx
>
>am I missreading this or what is the explanation?
>
>
>thanks
we use PIC compatibility mode which means that [noparse][[/noparse]inside the SX] four clock
cycles are required for each instruction. In the BS2p, we're running in
Turbo mode which means only one clock per instruction. At the same
frequency, the BS2p would run four times faster than the BS2sx.
But ... higher clock frequencies mean higher current draw and we know that
the SX can cook small hot-dogs when it's running hard. So we knocked the
BS2p clock down to 20 MHz (the BS2sx runs at 50 MHz).
From an SX instruction basis, the BS2sx is running at approximately 12.5 MHz
and is, therefore, slower than the BS2p. Please keep in mind that a lot of
the BS2p code was rewritten for the Turbo, so there isn't a wholesale speed
change. PAUSE still takes a parameter in 1 millisecond units. Other
commands, like PULSOUT and PULSIN change because the faster speed -- in some
cases -- gives you better resolution.
I hope this makes better sense of what you're seeing.
-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas, TX
In a message dated 11/15/02 7:51:15 AM Central Standard Time, rad0@a...
writes:
> hello,
>
> the parallax web site seems to say that the bs2p is 20percent
> faster than the bs2sx
>
>
[noparse][[/noparse]Non-text portions of this message have been removed]
Thanks Tracy and Jon.
I guess the BS2p is faster over all except where it
had to be slowed down for compatibility sake, the pause,
and so forth...
So therefore, it's true and it makes sense to say it is faster.
Thanks
Original Message
From: <jonwms@a...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, November 15, 2002 12:10 PM
Subject: Re: [noparse][[/noparse]basicstamps] how is the BS2p faster than the BS2sx??
> It has to do with the way the onboard SX chip is programmed. In the
BS2sx,
> we use PIC compatibility mode which means that [noparse][[/noparse]inside the SX] four clock
> cycles are required for each instruction. In the BS2p, we're running in
> Turbo mode which means only one clock per instruction. At the same
> frequency, the BS2p would run four times faster than the BS2sx.
>
> But ... higher clock frequencies mean higher current draw and we know that
> the SX can cook small hot-dogs when it's running hard. So we knocked the
> BS2p clock down to 20 MHz (the BS2sx runs at 50 MHz).
>
> From an SX instruction basis, the BS2sx is running at approximately 12.5
MHz
> and is, therefore, slower than the BS2p. Please keep in mind that a lot
of
> the BS2p code was rewritten for the Turbo, so there isn't a wholesale
speed
> change. PAUSE still takes a parameter in 1 millisecond units. Other
> commands, like PULSOUT and PULSIN change because the faster speed -- in
some
> cases -- gives you better resolution.
>
> I hope this makes better sense of what you're seeing.
>
> -- Jon Williams
> -- Applications Engineer, Parallax
> -- Dallas, TX
>
>
> In a message dated 11/15/02 7:51:15 AM Central Standard Time,
rad0@a...
> writes:
>
>
> > hello,
> >
> > the parallax web site seems to say that the bs2p is 20percent
> > faster than the bs2sx
> >
> >
>
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>