×

Please see all COVID-19 updates here as some shipments may be delayed due to CDC safety and staffing guidelines. If you have an order or shipping question please refer to our Customer Support page. For technical questions please check out our Forums. Thank you for your continued support.

Beginning Embedded Electronics - 11


Common Mistakes, Tips and Tricks

  1. All grounds need to be connected together.
  2. TX/RX loop back trick: When in doubt of a serial conversion circuit, short the TX and RX pins together to get an echo.
  3. Normal length wires for breadboard connections: Don't use a 9" wire where a 2" wire will do.
  4. Minimize short potential in your breadboard wiring: Don't expose an inch of wire from the insulation if all you need is 1/4".
  5. You will learn best when you have a *simple* project to work on. Don't create the 'house-pet robot' just yet.
  6. Google is, of course, your friend. When you don't know, go do some research.
  7. for(x = 0 ; x < 400 ; x++) : If x is defined as an 8-bit integer, the for loop will loop forever!
  8. Soldering basics: Wet your @#$% sponge.
  9. Take your time with ground plane solder joints. Do not be fooled by a cold joint.
  10. Never trick yourself into thinking you're that good. Print out a 1:1 and compare the footprints!
  11. Check that TX and RX are wired correctly to all peripherals. TX/RX swap is the one of the greatest causes of PCB failures.
  12. When laying out a PCB with SMD micros, don't forget to include the programming port!
  13. Don't run silkscreen across pads.
  14. Connector PCB footprint mis-numbering: always check the pin number on your connector - they can have very obfuscated schemes.
  15. In Eagle, use vector fonts only!
  16. Review your gerber files before submitting them.

Lecture 1 - Background and Power Supply

Lecture 2 - How to Get Code Onto a Microcontroller

Lecture 3 - What is an oscillator?

Lecture 4 - UART and Serial Communication

Lecture 5 - AVR GCC Compiling

Lecture 6 - Soldering Basics

Lecture 7 - SMD Soldering

Lecture 8 - Eagle: Schematics

Lecture 9 - Eagle: PCB Layout

Lecture 10 - Eagle: Creating a new part

Common Mistakes, Tips and Tricks

Comments 6 comments

  • Hi, all! I have found way to print PCB negative ( I use photoresist). In PCB editor go to file-CAM processor, select device PS_INVERTED. Then We have a file PostScript. But drawing our PCB placed on bottom side! I think, spend a sheet A4 of film for 50mm*50mm it isn't good. It was edited by manual in GIMP before. Not so good - we'll have paint 3200x4500 kilopoint if we need 600 DPI resolution. But- .PS and .EPS files are just text. We need open it and after

    /EU { 254 div 0.072 mul } def

    /inch { 72 mul } def

    insert

    0 inch 7 inch translate .

    And our PCB will move up to (7 inches in the example).

  • An 8 bit signed integer can be -128 (0b10000000) to +127 (0b01111111). An unsigned 8 bit integer can be 0 to 255 (0b11111111).

  • In my schematic I use the FTDI_BASIC for the Sparkfun.lbr. However, I noticed that in the package the pins names are backwards.
    GRN is named DTS and ect.

  • If an 8-bit integer is 255, and you increment it, it will rollover and become 0. 8-bit integers can only hold a value from 0 to 255. The condition part of the loop would have to be "x < 255" or lower.

    • You forgot to take into account that, by default, an 8-bit integer is signed, so +/- 127 is safe

  • Hey guys. These are a great selection of tips, I found a few of them useful even at my early stage. As a computer science student however, I have to know: Why does the for-loop in 7 increment indefinitely? I'm not very intimate with the characteristics of an 8-bit integer. With the data sets we work with, I find myself more commonly using 16- and 32-bit integers. Is it simply because of the limited range of the 8-bit integer? If so would not for(x = 0; x < 256; x++) also loop indefinitely? Great advice and great tutorials. I've spent nearly $100 at this site already, and it was worth every penny.