UNO R3, ATmega328 SMD, CH340

So many of them… Different versions, different types… Couldn’t it be one for all?

OK, so since 2020 we experience chip shortages on our market. That has lead to price increase. Suddenly - cheap UNO clones became not so cheap as it used to be. So, here we are with a bit cheaper UNO version.

First - it uses ATmega328 in SMD version, not THT one. That allow to make production more automated, lowering cost. As a drawback - having processor in socket allow to replace it if fails. With SMD version it is harder.

Second - use dedicated USB/Serial converted - cheaper and with better availability. So, here we have CH340 on board. Cheaper, but not versatile. ATmega16u2 used in “100% UNO R3 clone” can be reprogrammed and such board can work as keyboard or mouse when connected to computer. CH340 will be always USB/Serial converter. But it is a good thing - 99.9% of users don’t have to use UNO as other USB device.

Smaller SMD chip means we have more space on board (whole module keeps it size to be mechanically compatible with Arduino UNO) so there are additional pins. Each IO port is brought to these pins (so each IO is doubled as female socket and goldpin). There are 3 headers with 4 signals:

• TX, RX, 5V, GND
• SCL, SDA, 5V, GND
• 3.3V x 2 oraz GND x 2

It is good to have more GND or power pings…

Specification:

• Microcontroller: ATMega328P-PU
• USB Serial converter - CH340
• Operating Voltage: 5V
• External Input Voltage (recommended): 7-12V
• External Input Voltage (min/max): 6-20V
• Digital I/O Pins: 14
• Digital I/O Pins with PWM: 6
• Digital Inputs: 6
• DC Current per I/O Pin: 20 mA
• DC Current for 3.3V Pin: 50 mA
• Flash Memory: 32 KB (ATmega328P)
  • of which 0.5 KB used by bootloader
• SRAM: 2 KB (ATmega328P)
• EEPROM: 1 KB (ATmega328P)
• Clock speed: 16 MHz

Set includes:

• UNO R3 SMD board
• 1x40 goldpin (not soldered in)