v0.2 first build

A project log for Tiny Bit Dingus

Every Day Carry bit flipper

ajlittajlitt 06/30/2015 at 05:570 Comments

I nearly burnt the first v0.2 as I didn't have the thermocouple placed correctly. The LED did cook, but I have a long strip of them so no big deal.

So far it works, the ROM bootloader enumerating under Linux with no problems. LED and pins will need to be exercised.

There are already a couple of problems I plan to fix in the next iteration. Most obvious is the silk text for the pin labels is too small to print properly, and would be illegibly small even if it did. It would be helpful if there was a silk placement marker for the plastic shim like v0.1. On the stencil, I should have made the test pad cream-less, and possibly use a smaller footprint. I should also make separate stencils for the two USB variants otherwise I have to clean paste from the micro USB footprint.

I realized that I mistook I2C1_SCL as being the alt function for the boot pin and placed it next to GND so I can put a 2 pin jumper on to force ROM boot. I2C1_SDA is the correct pin, and I will swap the two in v0.3. Finally, the header on the next version will use the header footprint with locating pegs as centering it by hand is a pain.

Pics in the gallery.


The LED blinkens and the KSDK USB-CDC demo works great. The changes I want to make for v0.3 are minor, but before I commit to more PCBs and stencils I want to test out I2C, SPI, and UART, and try building up another board with the microUSB header.