Return-Path: X-Spam-DCC: paranoid 1290; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.0 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE,HTML_TINY_FONT autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u1KFrFbE025927 for ; Sat, 20 Feb 2016 16:53:15 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aX9mD-0006hX-Ae for rs_out_1@blacksheep.org; Sat, 20 Feb 2016 15:48:57 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aX9mC-0006hO-Qm for rsgb_lf_group@blacksheep.org; Sat, 20 Feb 2016 15:48:56 +0000 Received: from mail-wm0-f52.google.com ([74.125.82.52]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1aX9lA-0007Jl-VX for rsgb_lf_group@blacksheep.org; Sat, 20 Feb 2016 15:48:55 +0000 Received: by mail-wm0-f52.google.com with SMTP id g62so104931759wme.0 for ; Sat, 20 Feb 2016 07:47:37 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=a9dMoYjBBBvKrgA+uvzJrhft8/Jc5IqIT1ow8VhqSes=; b=0M21wJwNhWoWh3WAgyUwme9hEkd3bD1vIxQHu56x9yHazpGEFnvw4R/8BHUtnjkWZ4 NRXeo7fHemHj/lIuq07KqThExiri10vFKek23mxjURP/a8sjuk6izs0QoEkW+I8E73zs 7FOjF4cyG/UXV5ff51Gf9MFU5p0tIqByQrPCES1SEHzoU+B5P2hzV3+oyqhVydtSugTt PCUqz48yiZ4TdngjvsHnn4o6crELYinGpr4/DvwR8lWw7eM8WgLNgkI7fHLNFN3b8JyK rZMbzDfGG2YeLrjiufkbo76A+bzMWeo68uP7gxuupR6rNu0pcOPdMgA8wxy7/q2dQ/wQ 17cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=a9dMoYjBBBvKrgA+uvzJrhft8/Jc5IqIT1ow8VhqSes=; b=M7kETeGkElueP3+FQ5lTUoxKm/8u1ClmaODk0mrWfNG3/qOswIRhpqB5VWcG79jh7C 3igwllUww/q2WE20VjNcrvo/Xdb27AdmIKL1Pza9TytqRVjJw6cIQ106wq0oIVwzrh42 5bktthnxhv6jNTNs2aKDI1QWKHDuXKpDjceLrVOksLRF5BxRiGjRbpUWTKf2amvOKX6u TGKk7GXItpPtNvO7g7HpQt4DbsqX9tah+ZR5zYyDxIn54hLF8CdbxbRLUaWzL3CjtQjf HlU1SzZ+muq8CbUn6IqlD8FbRk9CBG8/OylnzRqAUbeQGuhBYi8bXorP/AjkfY0cDlLA aqTg== X-Gm-Message-State: AG10YOSn4rLgpyNsnaIsLgddYVk5aRwXeB8QAHeg6yWZe5hvYiPvkhFuFYy+tOJZBZmpZgcb4GUlVreJI3wgTg== MIME-Version: 1.0 X-Received: by 10.194.113.130 with SMTP id iy2mr4058573wjb.56.1455983211125; Sat, 20 Feb 2016 07:46:51 -0800 (PST) Received: by 10.28.187.213 with HTTP; Sat, 20 Feb 2016 07:46:51 -0800 (PST) In-Reply-To: <56C83E8A.5020503@freenet.de> References: <56BDED97.5060308@freenet.de> <56BE0364.6070503@gmx.net> <56BE1134.7060205@freenet.de> <56BE1D9E.6060200@freenet.de> <56C4DEFF.5060709@freenet.de> <56C83E8A.5020503@freenet.de> Date: Sat, 20 Feb 2016 15:46:51 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@yahoogroups.co.uk Cc: rsgb_lf_group@blacksheep.org X-Scan-Signature: 3115291393617ec6f23a73fc7137d37e Subject: Re: : Re: [rsgb_lf_group] Re: LF: PIC-based GPSDO with A/D converter / supported serial baudrates ? Content-Type: multipart/alternative; boundary=001a1130cffc1922f2052c358246 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 6904 --001a1130cffc1922f2052c358246 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Strictly, its doesn't run at non integer multiples or submultiples of 115200 at all. it runs at non integer DIVISORS (of the form N + M/8) from 3MHz So 1MBd, 500kBd etc. are exact, as are 4800000 Bd and 421052.6316 Bd (go on, work it out !) 115200, however is not exact. It works out at 3000000/(26 + 0/8) =3D 115384 baud But as that is only 0.16% in error, is quite close enough. Andy G4JNT On 20 February 2016 at 10:23, Wolfgang B=C3=BCscher dl4yhf@freenet.de [rsgb_lf_group] wrote: > > > Hello all, > > I can now confirm that the USB <-> UART (RS232) adapters with FTDI work > *much* better than the old one with the 'Prolific' chip. At the village's > local computer store, we found one labelled 'Delock Adapter USB 2.0 > 1x > Serial' which even had the info 'FTDI chipset' on the cardboard. > It runs happily also at non-integer multiples of 115200 bit/sec, e.g. 500 > kBit, and so far not a single byte has been lost. The driver has an extra > configuration screen to adjust the USB packet to up to 4096 bytes, i.e. t= he > hardware(?) buffer is large enough for a dozen milliseconds even at large > sampling rates. Gives some confidence that there is no bottleneck, and no > samples get lost on the USB. > > The CIC decimator (which decimates the 12-bit ADC values by 8) produces a > few additional bits for each output sample, which I don't want to sacrifi= ce > in the frame format. So simply sending out 16 bits per sample, least > significant byte first, should do the job. The plan(!) is that the receiv= er > (PC) can start or stop the data acquisition by sending a single-character > "command", so when the digitized samples start pouring in, the receiver > always knows the first received byte contains bits 7..0 of an analog > sample. Plus, it prevents that the stupid windows plug-and-play system > accidentally thinks the input from the A/D converter is a 'ballpoint > mouse'... > > 73, > Wolf . > > > Am 19.02.2016 um 23:34 schrieb Andy Talbot andy.g4jnt@gmail.com > [rsgb_lf_group]: > > Oddly, that is very nearly exactly what I'm doing now with the test PIC > module > Digitising at 40kHz and sending the results as a 12 bit word. The first > byte carries the 6 lower bits with its highest two set to '00' > > The second byte carries the upper 6 bits with its two MSBs set to '11'. > Its actually only a ten bit word as that is all the A/D converter in the > PIC can manage, the mechanism is in place for a 12 bit value. > > 40kHz sampling is enough to digitise the entire 475kHz band and leave > enough margin for filter transition bands, and even at 10 bit sampling, i= s > fast enough to make decimation worthwhile to expand the dynamic range. > > I only did it as an exercise to prove the serial communication link would > work at that rate, but may be a useful module to have on the shelf. > > Andy G4JNT > > On 19 February 2016 at 21:17, ik2pii@gmail.com [rsgb_lf_group] < > rsgb_lf_group@yahoogroups.co.uk> wrote: > >> >> >> My more crazy idea: >> >> 12 bits can be divided in two 6 bits chunk. >> >> If you transmit 8 bit words you have 2bit/chunk spare. Set te 8th bit to >> 0 for the less significant chunk and 1 for the most significant chunk. T= he >> receiver can now recognize and assemble the 12 bit word. >> >> Of course the sender CPU must have some idle time for splitting the 12 >> bit word. >> >> More: if you transmit two 7bit word you can increase a little the data >> rate. >> >> >> >> 73 de Claudio ik2pii >> >> >> > > __._,_.___ > ------------------------------ > Posted by: =3D?UTF-8?Q?Wolfgang_B=3Dc3=3Dbcscher?=3D > ------------------------------ > Reply via web post > > =E2=80=A2 Reply to sender > > =E2=80=A2 Reply to group > > =E2=80=A2 Start a new topic > > =E2=80=A2 Messages in this topic > > (9) > Visit Your Group > > > > [image: Yahoo! Groups] > > =E2=80=A2 Privacy =E2=80=A2 > Unsubscribe > =E2= =80=A2 Terms > of Use > > . > > __,_._,___ > --001a1130cffc1922f2052c358246 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Strictly, its doesn't run at non integer multiple= s or submultiples=C2=A0of 115200 at all.

it runs a= t non integer DIVISORS (of the form N + M/8)=C2=A0=C2=A0 from 3MHz

So 1MBd, 500kBd etc. are exact,
as are =C2=A048= 00000=C2=A0Bd =C2=A0 and 421052.6316 Bd (go on, work it out !)
115200, however is not exact.=C2=A0 It works out at=C2=A0=C2= =A0=C2=A0 3000000/(26 + 0/8) =3D 115384 baud
But as that is only = 0.16% in error, is quite close enough.=C2=A0

Andy= =C2=A0 G4JNT


On 20 February 2016 at 10:23, Wolfgang B=C3=BCscher <= a href=3D"mailto:dl4yhf@freenet.de">dl4yhf@freenet.de [rsgb_lf_group] <= span dir=3D"ltr"><rsgb_lf_group@yahoogroups.co.uk> wrote:
=20
=C2=A0
=20 =20

=20 =20 Hello all,

I can now confirm that the USB <-> UART (RS232) adapters with FTDI work *much* better than the old one with the 'Prolific' ch= ip. At the village's local computer store, we found one labelled 'D= elock Adapter USB 2.0 > 1x Serial' which even had the info 'FTDI chipset' on the cardboard.
It runs happily also at non-integer multiples of 115200 bit/sec, e.g. 500 kBit, and so far not a single byte has been lost. The driver has an extra configuration screen to adjust the USB packet to up to 4096 bytes, i.e. the hardware(?) buffer is large enough for a dozen milliseconds even at large sampling rates. Gives some confidence that there is no bottleneck, and no samples get lost on the USB.

The CIC decimator (which decimates the 12-bit ADC values by 8) produces a few additional bits for each output sample, which I don'= t want to sacrifice in the frame format. So simply sending out 16 bits per sample, least significant byte first, should do the job. The plan(!) is that the receiver (PC) can start or stop the data acquisition by sending a single-character "command", so when = the digitized samples start pouring in, the receiver always knows the first received byte contains bits 7..0 of an analog sample. Plus, it prevents that the stupid windows plug-and-play system accidentally thinks the input from the A/D converter is a 'ballpoint mouse'.= ..

73,
=C2=A0 Wolf .
=C2=A0

Am 19.02.2016 um 23:34 schrieb Andy Talbot andy= .g4jnt@gmail.com [rsgb_lf_group]:
=20 =20
Oddly, that is very nearly exactly what I'm doin= g now with the test PIC module=C2=A0
Digitising at 40kHz and sending the results as a 12 bit word.=C2=A0 The first byte carries the =C2=A06 lower bits with it= s highest two set to '00'

The second byte carries the upper 6 bits with its two MSBs set to '11'. =C2=A0 =C2=A0Its actually only a ten bit wor= d as that is all the A/D converter in the PIC can manage, the mechanism is in place for a 12 bit value.

40kHz sampling is enough to digitise the entire 475kHz band and leave enough margin for filter transition bands, and even at 10 bit sampling, is fast enough to make decimation worthwhile to expand the dynamic range.

I only did it as an exercise to prove the serial communication link would work at that rate, but may be a useful module to have on the shelf.

Andy =C2=A0G4JNT

On 19 February 2016 at 21:17, ik2pii@gmail.com [rsgb_lf_group] <rsgb_lf_group@yahoogroups.co.uk&g= t; wrote:
=C2=A0

My more crazy idea:


12 bits can be divi= ded in two 6 bits chunk.

If you transmit 8 b= it words you have 2bit/chunk spare. Set te 8th bit to 0 for the less signif= icant chunk and 1 for the most significant chunk. The receiver can now reco= gnize and assemble the 12 bit word.

Of course the sende= r CPU must have some idle time for splitting the 12 bit word.

More: if you transm= it two 7bit word you can increase a little the data rate.

=C2=A0

73 de Claudio ik2pi= i




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Posted by: =3D?UTF-8?Q?Wolfgang_B=3Dc3=3Dbcscher?=3D <dl4yhf@freenet.de> =
Repl= y via web post =E2=80=A2 Reply to sender =E2=80=A2 Reply to group =E2=80=A2 Start a new topic =E2=80=A2 Messages in this topic (9)
=20 =20
3D"Yahoo!
=E2=80=A2 Privacy =E2=80=A2 Unsubscribe =E2=80=A2 Terms of Use

=20 =20 =20 =20
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