Display with Dual Serial input

To follow the communication in a system (Wifi, Lora radio etc.) on both send and receive side
in real time, I built this one. It has two independent STM32F103 microcontrollers and two ST7789
TFT-s built together, one for each serial channel. The user can adjust baud rate, font size, scroll
in a selected STM32.
Each side can display 300 or 1200 characters from a 8192 byte buffer. If new characters are received,
the display will be refreshed.

The 3D printed parts are made for the 1.3" IPS display with 12 pin FPC connector, two of these are mounted
tight to each other. The same 3D part holds two STM32 microcontrollers on the back side. I have used
STM32 chips soldered on 48 pin adapter PCB, this is much compacter than the Blue Pill. For a minimal
system only a crystal,a few capacitors, resistors are necessary. I use a fine tip soldering iron at 310C
to solder the chip (0.5mm between pins) on the adapter PCB as well as soldering 0.25mm enamel wires
on the FPC connector (0.7mm between pins). Apply a thin layer of flux paste on the PCB. Position
the chip on it. Start with a corner pin. Keep the soldering iron in the axis of the pin, melt very little
fresh solder on tip, touch the solder tip to the chip pin's tip/end (never from the side), let it
warm up and check the result. Take 2-3 pins maximum at once. Should two pins flow together, remove the excess solder with litze.
The FPC connector is wired the same way.

The bigger case has room for the chinese Blue Pill STM32F103 controllers if you prefer that.

Supply built in: Li-Ion phone battery, TP4056 charger, round torch switch, HT7333. Replace the 1k2 resistor on the TP4056 board (pin 2 on the IC) with 5k6 to reduce charge current to 200mA.

The pushbuttons L to R : scroll up , scroll down, select left, select right, font size, baud rate.
Left and right selects which microcontroller responds to pushbuttons.
The microcontroller quits the setup menu, when signal is detected on the serial input.

Displaying hex data : Replace tft.write(buf[j % bufsize]); with tft.print(buf[j % bufsize],HEX); and print a delimiter too in the code.
Set "left" or "right" in the code (main loop) depending which side's code is compiled.

Parts available at Ebay, Aliexpress.

Anet

A8

200

20