This is an old revision of the document!
# LittleWire
# Overview
I can't think of anything to add to the official description of the LittleWire. For me, it's a cool tool to build, and a cool tool to have on hand, mostly for programming AVR chips.
* usbtinyisp compatible AVR programmer. * 4 channel GPIO. * ADC with 10 bit resolution. * 2 parallel hardware PWM outputs. * SPI interface. * I2C interface. * 1-Wire interface * WS2812 RGB LED interface. * Multiple device support.
# Perfboard
A while back, I used a round piece of perfboard to make a smd-like LittleWire… No schematics, it's directly inspired from the Schematic of the Little Wire. The only difference is: D+ and D- are swapped to make it easier to solder…
It's a little bit messy, but it worked, and still does its job !
# SMD
I was a little bored and wanted to practice SMD soldering, just for fun. So I made an SMD version of the LittleWire.
* Small footprint * MiniUSB connector * Easy to use header ⇒ Can be plugged in a breadboard ! * Micronucleus bootloader
## PCB #### v1.0 I still haven't made a schematic, so please, refer to the annotated PCB to assemble the board. Sorry, it's a little bit crowded, but everything should fit nicely… 600 DPI image, as usual around here…
Pin 1 of the Attiny is on the top right of the PCB, near D3
#### v1.1
I received some micro USB connectors, and wanted to try out my new PCB exposure box, so I replace the MiniUSB connector to a MicroUSB one. It made the board 3mm shorter !
Here's the new PCB:
## Components
Required
* D1, D2: 3.6v Zener Diodes * R1, R2: 39 Ohms * R3: 1.5 kOhms * C1: 1 µF * Attiny85 * 6 Pins Header, straight * MiniUSB connector
Optional
* C2: 68 nF * D3: Blue LED * R4: 1 kOhms
## Pinout
Pin 1 is the closest to the USB port. The pinout is then:
1. Vcc 2. Gnd 3. /Reset 4. SCLK 5. MISO 6. MOSI
Once you get used to this pinout, it's very handy to use ^^
## Firmware
I only re-host theses files in case the original goes missing. I haven't written those… Download: Micronucleus Bootloader (1.02) and LittleWire Firmware (1.3)
Flash an empty chip with:
avrdude -c usbtiny -p t85 -U flash:w:micronucleus-1.02.hex -U lfuse:w:0xe1:m -U hfuse:w:0x5d:m -U efuse:w:0xfe:m
And then use the Micronucleus software to flash the LittleWire firmware.
## Result
