On my samples, these are a very strong 1K.Ģ. The pullup resistor on the ATMEGA328P chip is given as 10K. The existing 1K resistors between CH340G TX/RX (Pins 2 & 3 ) and ATMEGA328P-AU RX/TX (pins 30 & 31) to be bridgedġ. Tx and Rx Leds disabled by removing the correspondin resistors. USB TTL Serial adapter based on Arduino Nano CH340G cloneĠ.1 uF between CH340G DTR (pin 13) and Nano pin A6ġ0K ohm pullup between Nano pin A6 and Vccġ0uf-22uF capacitor between Nano Reset pin and ground to be present when connecting to target system. I have also used it to upload sketches to an Adafruit Huzzah ESP8266 breakout board which is no mean feat because this is notoriously sensitive about which USBTTL device it will accept, which I guess is at least partly due to the very simple voltage level shifter on its Rx pin (a 1n4148 diode) which prevents the USBTTL device bringing the pin fully low and stops it pulling it high at all. In the breadboard picture, the Nano is set up to load the blink sketch onto a ATMega328P target system. RX0 RX ( via 1K resistor ) yes: Rx to Rx in this caseĪlso, the Nano Reset pin has a 10uF (or so) capacitor to ground to prevent it from being reset during the time an upload is sent to the target system. TX1 TX ( via 1K resistor ) yes: Tx to Tx in this case These last changes were necessary to get a reasonably reliable upload to the Adafruit Huzzah (see below) Other harware changes are disabling the Rx/Tx Leds and bridging the two 1K resistors in the serial lines between the CH340G and the ATMega328P. The sketch runs on the Nano and detects the falling edge on the the DTR and propogates a 100uS low pulse to reset the target system as required. There is also an external 10K pullup resistor added on A6. This hardware change consists of a 0.1 uF capacitor between the DTR pin of the CH340G and pin A6 of the Nano. Adafruit Learning System Pro Micro Pinout (red) Arduino NANO Pinout Diagram A DIY Arduino data logger for 10 from 3 components (2014) Micro SD Card. A hardware change is made to the Nano to enable a sketch to detect the falling edge of the DTR pin on the CH340G. This works with the standard Chinese Nano clone which has a CH340G such as is described here with a schematic diagram: Arduino Nano CH340 – schematics and details – This article discusses about the technical specs most importantly the pinout and functions of each and every pin in the Arduino Nano board. The Nano board weighs around 7 grams with dimensions of 4.5 cms to 1.8 cms (L to B). The Pro Mini's pins surround three of the. Schematic and Pin-out The schematic of the Pro Mini can be broken down into three blocks: the voltage regulator, the ATmega328 and supporting circuitry, and the headers. This is intended to be part of a larger programmer project but it also works as a stand alone system and could be useful for those who have a spare Nano but no USBTTL adapter. The Arduino Nano, as the name suggests is a compact, complete and bread-board friendly microcontroller board. Make sure to check out the board and install the respective driver for your USB-to-serial converter. I've converted an Arduino Nano clone into USBTTL adapter to upload sketches and view the serial console for 5 volt tolerant devices which don't have a USB interface such as a barebones ATmega328P, an Arduino mini, Adafruit Huzzah ESP8266 etc.
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