lfuse, hfuse and efuse refer to low, high and extended fuse bits, respectively We are setting the fuses at the same time as uploading the bootloader and the plaid firmware. -U lfuse:w:0xF7:m -U hfuse:w:0xD0:m -U efuse:w:0xfc:m are the fuse bits.If you are not in the folder where this is located then you will need to specify the filepath as well as the filename. -U flash:w:'plaid_default.hex':a is the.If you changed this in the avrisp sketch then change it here too Check >menu>port in the Arduino software if unsure. It is highly likely that this is the same for you, but could be different if, for instance, you have other USB devices connected. -P /dev/ttyUSB0 is the target port where the Nano is located.-p m328p is the target chip on the keyboard, which is an ATmega328p.We are using an arduino as a programmer, but we made it into an avrisp using the sketch earlier

What’s going on here? We execute avrdude with a series of arguments, comprising the following in order avrdude -u -c avrisp -p m328p -P /dev/ttyUSB0 -b 19200 -U flash:w:'plaid_default.hex':a -U lfuse:w:0xF7:m -U hfuse:w:0xD0:m -U efuse:w:0xfc:m In the same terminal window, enter the following. What we’re doing is concatenating the plaid firmware with the bootloader so that not only do we have a working keyboard but also the ability to upload new firmware by usb in future. Then append the contents of this hex file, which comes from the USBASPLoader repository. Edit this file in a text editor to remove the last line, which should read :00000001FF. This compiles a hex file of the keyboard firmware. In a terminal window in your qmk folder, type make dm9records/plaid:default. Thanks to Github user itsnoeasy, this is how I made it. You can skip the rest of this section until Burn the bootloader unless you are interested in where it came from. The straightforward command line wayīy far the easiest way to do this is to download this hex file I made earlier. At this point reconnect your Arduino to your computer using the USB cable. There are a few ways to make and burn the bootloader. With this in mind, connect each pin to the arduino pin named below: If pin 1 is at the top left we read the numbers left to right and up to down. The arrow on the plaid silkscreen next to one of the ISP pins is designated pin 1. From the pcb layout I worked out what the pinout should be for the 6 pins, outlined below. According to this site, the capacitor is needed to keep the reset pin high.Ĭonnect wires between the 6 pins on the plaid keyboard labelled “ISP” to the arduino. Another peculiarity of the Nano, you need to place a 10nF electrolytic capacitor between ground and reset (negative to ground). With a Nano, it is best to plant it on a breadboard and use Male-female jumper wire to make the connection. Prepare the keyboardįirst prepare the hardware, starting by disconnecting your Arduino from your computer. Once this sketch is uploaded the Arduino has become an AVRISP programmer with a baud rate of 19200 (different speeds can be set but this is the default in the sketch). My Nano was old and a cheap clone so I needed to set the board as “Arduino Nano” and processor “ATmega328P(Old Bootloader)”. Upload the inbuilt example sketch called ArduinoISP using the Arduino software to the Arduino board.

Computer with the following software installed:Ĭonnect the Arduino to your computer using the USB port.

Female-female jumper wire (if using an uno).

Male-female jumper wire and breadboard and 10nF electrolytic capacitor (if using a nano) OR.

USB cables (micro for keyboard, plus a compatible one for your Arduino if different).Arduino (I used a Nano but an Uno is typically used).These instructions were successfully used on the plaid keyboard but are also likely to be useful for discipline, discipad, torn, lumberjack and other through-hole mechanical keyboards with the same atmega328p chip.

So I decided to write down a full list of instructions, based on the use of an Arduino, which far more people own. It seemed like there was no good instructions to be found anywhere, and what information I did find relied on Teensy or dedicated serial programmers that I don’t own. I was finding it very difficult to burn the bootloader and upload the keyboard firmware to the plaid. Too much time and money later, I have made a custom split keyboard (based on the lily58) and also tackled an ortholinear keyboard called the plaid, made using through-hole components. About six months ago I was bitten by the mechanical keyboard bug and made a numpad (a yampad to be precise).

Arduino nano pinout isp