In the last article, I designed the MAX V CPLD 5M160 experimental board that sticks to the breadboard and placed an order with JLCPCB, a Chinese board manufacturer.
I received the substrate and stencils I had ordered, so I'd like to mount the parts.
Printing solder paste
Preparing to print
Place the substrate on a thick piece of cardboard and place the stencil on top of it.
I drilled holes in the substrate and stencil for alignment, so I put a thumbtack on it to align it. By drilling this hole, you can print solder paste accurately even with a narrow pitch of 0.4mm, such as MAX V CPLD, because you can align it exactly.
See the second half of the previous blog for more on how to drill holes.
Solder paste agitation
This solder paste is "TS391LT50" by CHIPQUIK. It is lead-free at low temperatures and can be stored at room temperature. You can also buy them at Martz Parts.
Soften this solder paste by stirring it well with a stick.
Put the solder paste on the back of the stencil and print the solder paste with a squeegee using a credit card or similar.
CHIPQUIK's solder paste "TS391LT50" has a fine particle size and prints beautifully even in small pitches. It is a great solder paste that can be stored at room temperature.
Component mounting
Using an SMD feeder printed on a 3D printer, the parts are picked with an electric vacuum pick.
When you pick a part from the SDM feeder, the orientation of the part is always face up and in a certain direction, which is very convenient for parts with a certain orientation, such as ICs and diodes.
The electric vacuum pick is a HAKKO 394.
The combination of a SMD feeder and an electric vacuum pick is great. It is more efficient than tweezers and reduces the mounting time.
Thanks to the electric vacuum pick, the mounting was completed in no time.
Reflow
It is reflowed in a convection oven, which can reduce the unevenness of the temperature inside the chamber by hot air. I use the Tescom Low Temperature Convection Oven TSF601, which allows me to reset the temperature at will during heating.
A K-type thermocouple thermometer is used to monitor the temperature while heating, but the set temperature and the temperature inside the cabinet are almost the same.
The temperature profile of CHIPQUIK's solder paste TS391LT50 is obtained by reflowing at 100°C for 2 minutes, 140°C for 1 minute, and 160°C for 1 minute.
Reflow is complete.
The substrate is completed by removing the discarded board and dividing the substrate.
Motion test
Connect the USB Blaster to JTAG connector and try to recognize MAX V CPLD from the software.
The USB Blastr I'm using is a cheap Terasic compatible product. There is also a cheaper Chinese made, but now I consider stability and use Terasic made.
If you have a Chinese-made one and you have a blue screen problem, you can work around it here.
When I ran "Auto Detect", "5M160Z" was displayed and I could see that the CPLD was correctly recognized.
I made a program that makes the LED glow when you touch the pin 1 with your finger. Since the MAX V series does not have a built-in clock, the noise transmitted from the fingers is used as a clock source and counted inside the CPLD to light the LEDs in turn.
I can write the program and it works fine.
The MAX V CPLD board that sticks to the breadboard is complete
Compared to the previous board (left in the photo), this board (right in the photo) is quite neat. It's easier to experiment than ever before because you can stick it on a breadboard.
You can buy here👇👇👇
