Are there any usb-serial adapters that folks find particularly
satisfactory? I've been using pl2303 and ft232 devices for a while,
bob prohaska <bp@www.zefox.net> wrote:
Are there any usb-serial adapters that folks find particularly satisfactory? I've been using pl2303 and ft232 devices for a while,
but wonder if there are other, newer types worth considering. The
main requirement is decent open-source compatibility. RTS/CTS would
be nice but not really necessary.
Attrition has taken the last of my spares and if there's something
better it would be good to know.
Crivens
I prefer to keep an old laptop with serial ports and cd/dvd drive.
Are there any usb-serial adapters that folks find particularly
satisfactory? I've been using pl2303 and ft232 devices for a while,
but wonder if there are other, newer types worth considering. The
main requirement is decent open-source compatibility. RTS/CTS would
be nice but not really necessary.
Attrition has taken the last of my spares and if there's something
better it would be good to know.
crn@nospam.com wrote:
bob prohaska <bp@www.zefox.net> wrote:... and what does one use RS232/RS485 for nowadays? I did use it a
Are there any usb-serial adapters that folks find particularly
satisfactory? I've been using pl2303 and ft232 devices for a while,
but wonder if there are other, newer types worth considering. The
main requirement is decent open-source compatibility. RTS/CTS would
be nice but not really necessary.
Attrition has taken the last of my spares and if there's something
better it would be good to know.
Crivens
I prefer to keep an old laptop with serial ports and cd/dvd drive.
while ago for driving a display at a distance but I2C with some long
wire drivers is now much easier in terms of availability of hardware
and so on. I've dropped RS232 sort of serial completely.
Are there any usb-serial adapters that folks find particularly
satisfactory? I've been using pl2303 and ft232 devices for a while,
but wonder if there are other, newer types worth considering. The
main requirement is decent open-source compatibility. RTS/CTS would
be nice but not really necessary.
The last time I had serial as opposed to USB
bob prohaska <bp@www.zefox.net> wrote:
Are there any usb-serial adapters that folks find particularly satisfactory? I've been using pl2303 and ft232 devices for a while,
but wonder if there are other, newer types worth considering. The
main requirement is decent open-source compatibility. RTS/CTS would
be nice but not really necessary.
Attrition has taken the last of my spares and if there's something
better it would be good to know.
Crivens
I prefer to keep an old laptop with serial ports and cd/dvd drive.
... and what does one use RS232/RS485 for nowadays?
crn@nospam.com wrote:
I prefer to keep an old laptop with serial ports and cd/dvd drive.
Not much use for modern stuff, where it's all 'TTL' RS232, ie 5v or 3.3v voltage levels, rather than +/-12V as you get on a DB9.
FT23x would be my top recommendation, since they're bulletproof.
CP210x is fine
MCPxxx is fine too
PL2303 is ok
CH340 is cheap'n'nasty
In article (Dans l'article) <um9b57$2ivcm$2@dont-email.me>, The Natural Philosopher <tnp@invalid.invalid> wrote (écrivait) :
The last time I had serial as opposed to USB
USB = universal SERIAL bus...
In article (Dans l'article) <um9b57$2ivcm$2@dont-email.me>, The Natural Philosopher <tnp@invalid.invalid> wrote (écrivait) :
The last time I had serial as opposed to USB
USB = universal SERIAL bus...
In message <tjil5k-c0j9.ln1@esprimo.zbmc.eu>
Chris Green <cl@isbd.net> wrote:
... and what does one use RS232/RS485 for nowadays?
Embedded programming.
OK, to be pedantic, it's more often at 5V or 3V3 logic levels than RS-232, but if we just think of it as serial, it's widespread.
David Higton <dave@davehigton.me.uk> wrote:
In message <tjil5k-c0j9.ln1@esprimo.zbmc.eu>
Chris Green <cl@isbd.net> wrote:
... and what does one use RS232/RS485 for nowadays?
Embedded programming.
OK, to be pedantic, it's more often at 5V or 3V3 logic levels than RS-232, but if we just think of it as serial, it's widespread.
Is it really? I have a number of RPis and a couple of Beaglebone
Blacks but, as I said earlier, I stopped using RS-232 serial quite a
while ago. It was just getting harder and harder to actually find
hardware that used it. For example I did use it for a while to drive
a remote LCD display but the RS-232 capable backpacks are now
difficult to find whereas I2C backpacks are plentiful and cheap as
chips.
Not much use for modern stuff, where it's all 'TTL' RS232, ie 5v or 3.3v voltage levels, rather than +/-12V as you get on a DB9.
FT23x would be my top recommendation, since they're bulletproof.
CP210x is fine
MCPxxx is fine too
PL2303 is ok
CH340 is cheap'n'nasty
And that's assuming they're genuine and not knockoffs.
https://wiki.freebsd.org/USB/Peripherals/Serial
has some more info
Chris Green <cl@isbd.net> wrote:
David Higton <dave@davehigton.me.uk> wrote:
In message <tjil5k-c0j9.ln1@esprimo.zbmc.eu>
Chris Green <cl@isbd.net> wrote:
... and what does one use RS232/RS485 for nowadays?
Embedded programming.
OK, to be pedantic, it's more often at 5V or 3V3 logic levels than RS-232,
but if we just think of it as serial, it's widespread.
Is it really? I have a number of RPis and a couple of Beaglebone
Blacks but, as I said earlier, I stopped using RS-232 serial quite a
while ago. It was just getting harder and harder to actually find
hardware that used it. For example I did use it for a while to drive
a remote LCD display but the RS-232 capable backpacks are now
difficult to find whereas I2C backpacks are plentiful and cheap as
chips.
Many embedded widgets, including RPi 5 by default and other RPis if you configure it so, have a TTL serial port lurking on the board somewhere, by which you can get the boot messages and maybe a recovery console. It is often not labelled, but the likes of OpenWRT have details of how to find them for a lot of home router hardware.
This is also Modbus, a serial port using RS485 differential signalling,
which is very common for talking to industrial stuff.
Theo <theom+news@chiark.greenend.org.uk> wrote:
Chris Green <cl@isbd.net> wrote:
David Higton <dave@davehigton.me.uk> wrote:
In message <tjil5k-c0j9.ln1@esprimo.zbmc.eu>
Chris Green <cl@isbd.net> wrote:
... and what does one use RS232/RS485 for nowadays?
Embedded programming.
OK, to be pedantic, it's more often at 5V or 3V3 logic levels than RS-232,
but if we just think of it as serial, it's widespread.
Is it really? I have a number of RPis and a couple of Beaglebone
Blacks but, as I said earlier, I stopped using RS-232 serial quite a while ago. It was just getting harder and harder to actually find hardware that used it. For example I did use it for a while to drive
a remote LCD display but the RS-232 capable backpacks are now
difficult to find whereas I2C backpacks are plentiful and cheap as
chips.
Many embedded widgets, including RPi 5 by default and other RPis if you configure it so, have a TTL serial port lurking on the board somewhere, by which you can get the boot messages and maybe a recovery console. It is often not labelled, but the likes of OpenWRT have details of how to find them
for a lot of home router hardware.
But that's already there, you don't need a USB to RS232 adapter to use
it. ... or are you saying that you have another RPi that you're using
to talk to it?
This is also Modbus, a serial port using RS485 differential signalling, which is very common for talking to industrial stuff.
Yes, I've sort of looked at that because it's closely related to
CANbus, however will a standard USB to 'serial' adapter talk to it?
Chris Green <cl@isbd.net> wrote:
David Higton <dave@davehigton.me.uk> wrote:
In message <tjil5k-c0j9.ln1@esprimo.zbmc.eu>Is it really? I have a number of RPis and a couple of Beaglebone
Chris Green <cl@isbd.net> wrote:
... and what does one use RS232/RS485 for nowadays?
Embedded programming.
OK, to be pedantic, it's more often at 5V or 3V3 logic levels than RS-232, >>> but if we just think of it as serial, it's widespread.
Blacks but, as I said earlier, I stopped using RS-232 serial quite a
while ago. It was just getting harder and harder to actually find
hardware that used it. For example I did use it for a while to drive
a remote LCD display but the RS-232 capable backpacks are now
difficult to find whereas I2C backpacks are plentiful and cheap as
chips.
Many embedded widgets, including RPi 5 by default and other RPis if you configure it so, have a TTL serial port lurking on the board somewhere, by which you can get the boot messages and maybe a recovery console. It is often not labelled, but the likes of OpenWRT have details of how to find them for a lot of home router hardware.
This is also Modbus, a serial port using RS485 differential signalling,
which is very common for talking to industrial stuff.
Theo
One use for a Pi Zero or similar is as a simple debug tool to talk to
random devices via software driving GPIO - might be UART, I2C or JTAG -
and then either plugged into your PC as a USB gadget (network) device, or connected via wifi. In that case the Pi is being your (unconventional)
USB to UART (or wifi to UART) adapter.
Many embedded widgets, including RPi 5 by default and other RPis if you >configure it so, have a TTL serial port lurking on the board somewhere, by >which you can get the boot messages and maybe a recovery console.
It's much more convenient to send a file to
OctoPrint and tell it to start printing than to have to move the printer's
SD card over to your computer, write a file to it, put it back in the printer, and select the file on the printer's control panel to begin printing.
... and what does one use RS232/RS485 for nowadays?
Chris Green <cl@isbd.net> writes:
... and what does one use RS232/RS485 for nowadays?
In my case, serial terminal, on headless computers. And sometimes
interfacing with retro stuff, for example I recently dug up my old HP48 calculators which talk 9600 bps and ymodem at best.
Are there any usb-serial adapters that folks find particularlyThere is a seller on Tindie called 8086 Consultancy that has a whole bunch of https://tindie.com/stores/8086net/items/ if you
satisfactory? I've been using pl2303 and ft232 devices for a while,
Are there any usb-serial adapters that folks find particularly
satisfactory? I've been using pl2303 and ft232 devices for a while,
but wonder if there are other, newer types worth considering. The
main requirement is decent open-source compatibility. RTS/CTS would
be nice but not really necessary.
Attrition has taken the last of my spares and if there's something
better it would be good to know.
Thanks for reading and any guidance.
In My Experience - MOST USB/SERIAL adapters work OK
in PI/OS. I think, despite brand names, there are only
a few actual chip-sets.
While Amazon reviews are a bit suspect, still DO
read them, with particular attention to Linux
remarks
IF you get stuck having to load virtual Winders
drivers ... then you haven't chosen wisely
Pi's can also do RS-232 directly. A bit less civil,
but it works.
56g.1183 <56g.1183@ztq4.net> wrote:
In My Experience - MOST USB/SERIAL adapters work OK
in PI/OS. I think, despite brand names, there are only
a few actual chip-sets.
While Amazon reviews are a bit suspect, still DO
read them, with particular attention to Linux
remarks
If you can find the chip number, that's the main thing. If there is a link to Windows drivers, downloading them and taking a look at the .inf file is a good clue.
IF you get stuck having to load virtual Winders
drivers ... then you haven't chosen wisely
There is no support for running virtual Windows serial drivers in Linux.
Pi's can also do RS-232 directly. A bit less civil,
but it works.
Pis can do *serial* directly, but not RS232. They only have 3.3V signal levels, so voltage conversion needed for RS232 or another voltage (1.8V, 5V, etc).
Pis can do *serial* directly, but not RS232. They only have 3.3V signal
levels, so voltage conversion needed for RS232 or another voltage (1.8V, 5V, >> etc).
Yep ... level-shifting chips are generally needed.
The MAX3232 will do it.
https://www.analog.com/media/en/technical-documentation/data-sheets/MAX3222-MAX3241.pdf
If you are talking to VERY old serial devices that still
expect some plus/minus 12v or more signals then you may
have to double-up, add a MAX232 after the 3232
...snip...
Anyhow, peruse the usual spots, AdaFruit, SparkFun,
Seeed. They may have a canned solution.
On 2024-01-04, 56g.1183 <56g.1183@ztq4.net> wrote:
...snip...
Anyhow, peruse the usual spots, AdaFruit, SparkFun,
Seeed. They may have a canned solution.
sound advice.
On 2024-01-04, 56g.1183 <56g.1183@ztq4.net> wrote:
Pis can do *serial* directly, but not RS232. They only have 3.3V signal >>> levels, so voltage conversion needed for RS232 or another voltage (1.8V, 5V,
etc).
Yep ... level-shifting chips are generally needed.
The MAX3232 will do it.
It does more than "level shift" it also inverts the signals. It will
accept 3v or 5v logic, even though supplied from a 3.3v supply.
https://www.analog.com/media/en/technical-documentation/data-sheets/MAX3222-MAX3241.pdf
If you are talking to VERY old serial devices that still
expect some plus/minus 12v or more signals then you may
have to double-up, add a MAX232 after the 3232
Maybe. But not as you say. You would need a simple 3v to 5v level
shifter (so as NOT to invert the signal) then the MAX232.
...snip...
Anyhow, peruse the usual spots, AdaFruit, SparkFun,
Seeed. They may have a canned solution.
sound advice.
On 1/4/24 7:27 AM, Jim Jackson wrote:
On 2024-01-04, 56g.1183 <56g.1183@ztq4.net> wrote:
Pis can do *serial* directly, but not RS232. They only have 3.3V signal >>>> levels, so voltage conversion needed for RS232 or another voltage (1.8V, 5V,
etc).
Yep ... level-shifting chips are generally needed.
The MAX3232 will do it.
It does more than "level shift" it also inverts the signals. It will
accept 3v or 5v logic, even though supplied from a 3.3v supply.
Properly wired, the MAX232 can deliver "real" RS-232 ... including
the negative voltages.
There IS still some equipment that expects
those kinds of signals ... albeit mostly early-80s. Some industrial
controllers of that vintage are still in use however.
Flow-control ... sticky. For RECEIVING no modern cpu/controller
is so slow that it cannot absorb such comms at even the highest
usual RS232 speeds. However those ancient devices you may be
communicating with may NOT be able to absorb the info so quickly.
Ergo you have to respect their flow-control lines. Serial comms
can be a pain in the ass. There are subtle issues.
https://www.analog.com/media/en/technical-documentation/data-sheets/MAX3222-MAX3241.pdf
If you are talking to VERY old serial devices that still
expect some plus/minus 12v or more signals then you may
have to double-up, add a MAX232 after the 3232
Maybe. But not as you say. You would need a simple 3v to 5v level
shifter (so as NOT to invert the signal) then the MAX232.
Again, depends on what you are trying to converse with.
Very old devices may expect/depend on those rather high
negative signal levels.
Properly wired, the MAX232 can deliver "real" RS-232 ... including
the negative voltages.
The 3232 does provide the negative and positive voltages but only at
+/-5.5v Which is fine for most modern stuff, but as you say below not
for some older stuff.
Again, depends on what you are trying to converse with.
Very old devices may expect/depend on those rather high
negative signal levels.
Indeed, which the max232 provides, +/- 12v. But it needs driving with 5v logic levels. Hence the need for the 3v-to-5v level shifters BEFORE the MAX232 inputs.
On 2024-01-07, Jim Jackson <jj@franjam.org.uk> wrote:
Properly wired, the MAX232 can deliver "real" RS-232 ... including
the negative voltages.
The 3232 does provide the negative and positive voltages but only at
+/-5.5v Which is fine for most modern stuff, but as you say below not
for some older stuff.
Which means the older stuff is broken and not really conforming to RS232 - the signals from the '3232 & Co *are* fully RS232-compliant.
Yes, I know broken stuff exists and if you need to interface to such stuff, you need better drivers, but the blame is on the broken equipment and not on the MAX3232.
Again, depends on what you are trying to converse with.
Very old devices may expect/depend on those rather high
negative signal levels.
Indeed, which the max232 provides, +/- 12v. But it needs driving with 5v
logic levels. Hence the need for the 3v-to-5v level shifters BEFORE the
MAX232 inputs.
When driving a RS232 load, the MAX232E output is specified at +-9V typical, +-5V guaranteed minimum - not +-12 (it internally doubles the +5V supply, so there is no way to get above 10V).
The MAX3232 output is +-5V minimum, and +-5.5V typical.
If you really need more output swing, you will have to use something like a SN75188 (with a 3.3V -> 5V level converter, and +-13V supplies) - at VCC=+-13.2V, these will drive +-9V guaranteed and +-10.5V typical.
With Vih=1.9V, these might even work from a 3.3V output without additional level translation.
Async is versatile, but a pain in the rump sometimes. Synchronous
serial is more civilized. However most equipment you'll ever come
across is async.
On 2024-01-05, 56g.1183 <56g.1183@ztq4.net> wrote:
On 1/4/24 7:27 AM, Jim Jackson wrote:
On 2024-01-04, 56g.1183 <56g.1183@ztq4.net> wrote:
Pis can do *serial* directly, but not RS232. They only have 3.3V signal >>>>> levels, so voltage conversion needed for RS232 or another voltage (1.8V, 5V,
etc).
Yep ... level-shifting chips are generally needed.
The MAX3232 will do it.
It does more than "level shift" it also inverts the signals. It will
accept 3v or 5v logic, even though supplied from a 3.3v supply.
Properly wired, the MAX232 can deliver "real" RS-232 ... including
the negative voltages.
The 3232 does provide the negative and positive voltages but only at
+/-5.5v Which is fine for most modern stuff, but as you say below not
for some older stuff.
There IS still some equipment that expects
those kinds of signals ... albeit mostly early-80s. Some industrial
controllers of that vintage are still in use however.
Flow-control ... sticky. For RECEIVING no modern cpu/controller
is so slow that it cannot absorb such comms at even the highest
usual RS232 speeds. However those ancient devices you may be
communicating with may NOT be able to absorb the info so quickly.
Ergo you have to respect their flow-control lines. Serial comms
can be a pain in the ass. There are subtle issues.
https://www.analog.com/media/en/technical-documentation/data-sheets/MAX3222-MAX3241.pdf
If you are talking to VERY old serial devices that still
expect some plus/minus 12v or more signals then you may
have to double-up, add a MAX232 after the 3232
Maybe. But not as you say. You would need a simple 3v to 5v level
shifter (so as NOT to invert the signal) then the MAX232.
Again, depends on what you are trying to converse with.
Very old devices may expect/depend on those rather high
negative signal levels.
Indeed, which the max232 provides, +/- 12v. But it needs driving with 5v logic levels. Hence the need for the 3v-to-5v level shifters BEFORE the MAX232 inputs.
On 1/7/24 2:50 PM, Jim Jackson wrote:
Indeed, which the max232 provides, +/- 12v. But it needs driving with 5v
logic levels. Hence the need for the 3v-to-5v level shifters BEFORE the
MAX232 inputs.
Probably true. I think the 3232 is 3.3 in/out so some kind3.3 in and 5v tolerant
of level-converter would be required between it and the 232.
Cheap, or you can make yer own, but it's an extra level of
complication.
Thing is, some of that old equipment (oft industrial) IS still
out there doing its job so a Fake-to-Real RS232 (might add a
couple other RS's) converter might be a worthwhile bit of kit
to have around.
There's also the issue of the flow-control lines. While modern
stuff is fast enough to not worry about it, the old equipment
might need to signal a brief stop while you are sending to it.
Buffers were often very small back then (and processing slow).
Async is versatile, but a pain in the rump sometimes. Synchronous
serial is more civilized. However most equipment you'll ever come
across is async.
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