Difference between revisions of "Hardware-set-ups"
m (Add ASCII schematic for DEV-18288 set up, very simple set up.) |
m (Add hardware set up description for testings serial port on Linux host with loopback cable.) |
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| + | == [[#top|^]] Serial port loopback test on Linux == | ||
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| + | In two terminal windows, programs `echo` and `cat` can be used to test a serial port connected to a loopback cable. This testing also effectively demonstrates the working of serial drivers under Linux. Works for USB-based FTDI cables which convert USB to a serial link. Works for the much older 16550 based serial port peripheral chips. | ||
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| + | A third and precursor command, `stty` is also needed to configure given serial port for sane operation during these tests. A couple of options to `stty` utility disable a default echoing behavior on given serial port. Another option suppresses a conversion or handling of carriage return bytes, e.g. stops serial port driver at some level from converting CR to CRLF. | ||
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| + | Invocation of stty is: | ||
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| + | stty -F /dev/ttyUSB4 -echo -onlcr | ||
Revision as of 19:42, 4 October 2022
(1) Rpi RP2040 DEV-18288 set up 2022 Q2:
On Rpi Sparkfun board, DEV-18288 have an LED connected from GPIO p0_7, through 22kOhm resistor to plus rail pin left of the USB-C connector.
+---------+ | 9| ^^ | 8| // | 7|---|>|---/\/\/---+ | 6| 22k | | 5| | | 4| | | 3| | | 2| | |3V3 GND| | |RST GND| | |GDN RX| | +--|+ TX| | | +---------+ | | | +------------------------------+
^ Serial port loopback test on Linux
In two terminal windows, programs `echo` and `cat` can be used to test a serial port connected to a loopback cable. This testing also effectively demonstrates the working of serial drivers under Linux. Works for USB-based FTDI cables which convert USB to a serial link. Works for the much older 16550 based serial port peripheral chips.
A third and precursor command, `stty` is also needed to configure given serial port for sane operation during these tests. A couple of options to `stty` utility disable a default echoing behavior on given serial port. Another option suppresses a conversion or handling of carriage return bytes, e.g. stops serial port driver at some level from converting CR to CRLF.
Invocation of stty is:
stty -F /dev/ttyUSB4 -echo -onlcr
