(r1) SerialPorts < IoT_Course

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---+ Using a second Serial Port

On the ESP32 UART0 is normally reserved for interactive use with REPL. Sometimes we need a !UART to communicate with external devices. Typical examples are:
   * fingerprint readers using a serial communication protocol
   * GPS modules
The ESP32 has 3 !UARTs of which however UART1 is reserved for use with flash memory. *However UART2 is free.*

Connect the USB to Serial adapter to the ESP32 as shown in the table below

|  USB to Serial Adapter  |  ESP32 pins  |
|  Rx  |  GPIO 17  |
|  Tx  |  GPIO 16  |
|  Gnd  |  Gnd  |
As a first quick test we can try to write "Hello World to UART2 to which we connect a minicom virtual terminal.

_thonny_ is connected to UART0 on /dev/ttvUSB0 (connect this first). <i>minicom </i>is connected to UART2 on /dev/ttyUSB1. Start minicom with:

_minicom -D /dev/ttyUSB1_

Here is the screen dump of the REPL session

<img alt="uart2.png" height="191" src="%ATTACHURL%/uart2.png" title="uart2.png" width="599" />

And this is what we see on minicom:

<img alt="uart2-minicom.png" height="209" src="%ATTACHURL%/uart2-minicom.png" title="uart2-minicom.png" width="559" />

... if you are too lazy to type, here is the corresponding script:

%ATTACHURL%/uart.py.txt

-- %USERSIG{UliRaich - 2020-05-09}%
---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
txt	uart.py.txt	r1	manage	0.2 K	2020-05-09 - 20:01	UliRaich
png	uart2-minicom.png	r1	manage	23.7 K	2020-05-09 - 19:57	UliRaich
png	uart2.png	r1	manage	23.6 K	2020-05-09 - 19:57	UliRaich

Topic revision: r1 - 2020-05-09 - UliRaich