Friday, September 18, 2020

108 key

Second SMT order from JLCPCB

$8 discount on 100mm x 100mm PCB assembly. This time with 110 4.5mm tactile switches. The only parts not assembled by JLCPCB were the Mini USB connector, ICSP header, PTC fuse and the socket for the ATmega32a.

I ordered 5 PCB's and had 2 assembled. I received the 3 unassembled boards with the 2 completed ones. I used the blank PCB as the bottom.

I used blue LEDs for the V-USB voltage regulator. These were basic items so did not have a setup fee. There is only one extended part, the tactile switches. $3 total additional setup fee. I also placed a footprint for standard zener diode in case the blue LEDs did not work.

The switches are rotated 15 degrees and overlapped to position them as close as possible and still have a square grid. On this particular board they had to manually solder the bottom right switch. I could tell because of the flux residue and there is much more solder on those joints than any of the others. The second board I received was perfect.

Every data pin on the ATmega32a is in use. 12 columns and 9 rows. 5 status LEDs. The USBASP switch on PD7 and the ICSP pins on the header. PD2 and PD4 for the V-USB connection. Same as I use on the ATmega328 on the Aardvark.

TMK supports the ATmega32 with this fork