Electronics Production

Task

I have this week worked with electronic production and completed the following:

• Characterized our PCB production process.
• Milled a PCB for an In-System Programmer.
• Soldered components to the In-System Programmer.

The People Behind

I completed majority of my work this week by following the instructions on Brians page about the FabTinyISP.

I recognize that FabTinyISP i one in the row of many AVR ISP programmers/boards and that the entire development is based on efforts of many people. I will (as Brian does) refers to Zaerc's FabTinyStar page for further information about the contributors.

See GIF for the proces of using FabModules to use a PNG-file to create a Roland SMR-20 compatible milling path (RML-file).

The steps below explains the milling process using Roland SMR-20:

1. Leveling the underlay of sacrificial material.
2. Fixture of the FR1 board using double sided tape.
3. Install bit (1/64’).
4. Zeroing XY-axis at a suitable location.
5. Lowering the bit to the top of the material.
6. Zeroing Z-axis and then raise the Z-axis.
7. Write Down Maschine Coordinates.
8. Mill the PCB.
9. Change bit (1/32’) and repeat step 5-8.

Lessons Learnt About Milling

• Don't over thighten the lock-screw.
• Draw a desired origin for easiers XY-zeroing.
• Make sure that the material is sufficiently mounted.
• Note the 'mashine position' after setting user origin.
• Always raise Z-axis after zeroing it.
• Be ready to pause if the milling does not look right.

Cleaning, Preparing and Checking PCB

The milled PCB needs some post processing before components can be soldered on.

I first dusted of all cut away material. I then washed the PCB in water and soap and ensured that all adhesive material was removed from the back.

Depending on the amount of offset selected while creating the RML-file there might be a need to manual remove residual copper from the front of the USB-tip. The copper was easily removed with a small knife.

I finally went through the PCB to check it for any unintentionally broken connections.

Required Software & Firmware

I followed Brians guide and completed the following on my Mac running High Sierra (OS 10.13.3):

• Download and install CrossPack.
• Download and extract the firmware source code
• Using Terminal to navigate to the firmware directory

Programming the ATtiny45

I then ran the following commands:

make

Opened the 'Makefile' and changed it to reflect that I am using the ATMEL ICE programmer.

PROGRAMMER ?= atmelice_isp

I plugged the board via a USB extension cable to a USB port and the red LED illuminated. Then I connected the ATMEL ICE programmer to the ISP header on my board (with the tap pointing towards the Attiny45). And ran the following command:

make flash

Everything until this point went exactly according to the guide. Instead of observing several progress bars while the ISP was programmed I received the following error message:

avrdude: usbdev_open(): did not find any USB device "usb"

Challenges Using ATMEL ICE on Mac

This lead to a weekend long investigation throught which I found several cahllenges, learned a lot but in the end unfortunately had to surrender.

I hope that the following highlights will contribute to the community (and that the community might reply with some answers):

• CrossPack includes AVRDUDE version 6.0.1
• AVRDUDE version 6.3 (released 16 Feb 2016) includes support for ATMEL ICE
• ATMEL ICE calls itself a USB HID device which thus is claimed by MacOS X and in 'High Sierra' requires addition of a signed kexts
• avrdude.conf file might need addition og the following programmer definition for the Atmel ICE:

programmer

  id = "atmelice_isp";

  desc = "Atmel-ICE (ARM/AVR) in ISP mode";

  type = "jtagice3_isp";

  connection_type = usb;

  usbpid = 0x2141;

;         

Closing Remarks and Conclusion

Messing around with Terminal, AVR software, programmer definitions, config and kext files has not just been a waste of time (though it at one point surely felt like it).

I have learned alot during this week and everything paid off the first day back in the FabLab. I confidently opened a Ubunto, installed software, downloaded firmware and ran commands according to the guide (but almost from memory).

Everything went smooth using the ATAVRISP2 programmer and I finally had a functioning FabTiny In-System Programmer.

Design Files

• FabTinyISP Traces 1000 DPI (6 kB)
• FabTinyISP Traces .RML-file (28 kB)
• FabTinyISP Cut 1000 DPI (1 kB)
• FabTinyISP Cut 1000 .RML-file (1 kB)

Noticable Work from other FabAcademists

• Brians page about FabTinyIPS (Online)