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Groups > comp.arch.embedded > #30356 > unrolled thread
| Started by | pozz <pozzugno@gmail.com> |
|---|---|
| First post | 2021-03-24 00:06 +0100 |
| Last post | 2021-05-10 09:46 +0200 |
| Articles | 2 on this page of 22 — 9 participants |
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Linux embedded and direction control of RS485 transceiver pozz <pozzugno@gmail.com> - 2021-03-24 00:06 +0100
Re: Linux embedded and direction control of RS485 transceiver upsidedown@downunder.com - 2021-03-24 07:28 +0200
Re: Linux embedded and direction control of RS485 transceiver Don Y <blockedofcourse@foo.invalid> - 2021-03-24 06:17 -0700
Re: Linux embedded and direction control of RS485 transceiver upsidedown@downunder.com - 2021-03-24 17:49 +0200
Re: Linux embedded and direction control of RS485 transceiver Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-24 18:32 +0200
Re: Linux embedded and direction control of RS485 transceiver upsidedown@downunder.com - 2021-03-24 19:22 +0200
Re: Linux embedded and direction control of RS485 transceiver David Brown <david.brown@hesbynett.no> - 2021-03-24 19:44 +0100
Re: Linux embedded and direction control of RS485 transceiver upsidedown@downunder.com - 2021-03-25 07:34 +0200
Re: Linux embedded and direction control of RS485 transceiver upsidedown@downunder.com - 2021-03-25 07:47 +0200
Re: Linux embedded and direction control of RS485 transceiver Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-24 21:13 +0200
Re: Linux embedded and direction control of RS485 transceiver upsidedown@downunder.com - 2021-03-25 07:39 +0200
Re: Linux embedded and direction control of RS485 transceiver David Brown <david.brown@hesbynett.no> - 2021-03-25 10:48 +0100
Re: Linux embedded and direction control of RS485 transceiver Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2021-03-25 16:33 +0200
Re: Linux embedded and direction control of RS485 transceiver Grant Edwards <invalid@invalid.invalid> - 2021-03-25 14:49 +0000
Re: Linux embedded and direction control of RS485 transceiver upsidedown@downunder.com - 2021-03-25 18:43 +0200
Re: Linux embedded and direction control of RS485 transceiver David Brown <david.brown@hesbynett.no> - 2021-03-26 09:47 +0100
Re: Linux embedded and direction control of RS485 transceiver Don Y <blockedofcourse@foo.invalid> - 2021-03-24 14:30 -0700
Re: Linux embedded and direction control of RS485 transceiver dalai lamah <antonio12358@hotmail.com> - 2021-03-24 11:48 +0100
Re: Linux embedded and direction control of RS485 transceiver pozz <pozzugno@gmail.com> - 2021-03-25 00:23 +0100
Re: Linux embedded and direction control of RS485 transceiver "A.P.Richelieu" <aprichelieu@gmail.com> - 2021-05-09 13:24 +0200
Re: Linux embedded and direction control of RS485 transceiver Uwe Bonnes <bon@hertz.ikp.physik.tu-darmstadt.de> - 2021-05-09 12:01 +0000
Re: Linux embedded and direction control of RS485 transceiver pozz <pozzugno@gmail.com> - 2021-05-10 09:46 +0200
Page 2 of 2 — ← Prev page 1 [2]
| From | Uwe Bonnes <bon@hertz.ikp.physik.tu-darmstadt.de> |
|---|---|
| Date | 2021-05-09 12:01 +0000 |
| Message-ID | <ifq17uFbfjaU1@mid.individual.net> |
| In reply to | #30603 |
A.P.Richelieu <aprichelieu@gmail.com> wrote: > Atmel (now Microchip) ARM products has a serial port which supports > handling the RS-485 direction in hardware. It also has an interrupt > which is triggered after a programmable delay has occured without any > receied characters. > Similar for recent STM32 U(s)arts. -- Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 1623569 ------- Fax. 06151 1623305 --------- (Phone also available during "mobile work")
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| From | pozz <pozzugno@gmail.com> |
|---|---|
| Date | 2021-05-10 09:46 +0200 |
| Message-ID | <s7aoc7$m98$1@dont-email.me> |
| In reply to | #30603 |
Il 09/05/2021 13:24, A.P.Richelieu ha scritto: > Den 2021-03-24 kl. 00:06, skrev pozz: >> I have an half-duplex RS485 bus with 10-20 different nodes. Some of >> them are 8-bit MCU based, one of them could be Linux embedded. >> >> It's half-duplex, so it's important for the transmitter node to >> disable the driver as soon as the last transmitted bit is shifted out. >> >> Many small low-cost MCU has interrupt on transmission complete, so the >> delay of disabling the driver is usually on the order of microseconds. >> >> Some new Cortex-M MCUs have an automatic control of external RS485 >> transceiver, so the delay is really zero. >> >> What happens in Linux embedded systems? Many of them are based on NXP >> i.MX CPUs and it seems they aren't able to control the RS485 direction >> in hardware, but some code is needed. This approach could increase the >> delay of disabling the driver in the order of milliseconds. >> >> Is it possible that a powerful CPU isn't able to control RS485 driver >> in hardware? > > Atmel (now Microchip) ARM products has a serial port which supports > handling the RS-485 direction in hardware. It also has an interrupt > which is triggered after a programmable delay has occured without any > receied characters. I know SAM D family MCUs has a nice SERCOM peripheral with RS485 direction in hardware. But my discussion was for Linux embedded, so MPUs (Cortex-A).
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