I don't know if this board's microcontroller is already programmed. If not, do I have to get the parts to program it--I never did this before so there are doubts I can do it. It's supposed to be a frequency counter and crystal tester. I already bought it and assembled it but the digits don't light up --the decimal points are soldered on the bottom and not on the top as shown on the website picture--the print on the board indicates that the decimal points should be on the bottom when soldered. The 5 cathode voltages are 5 volts negative as measured when powered and this is a common cathode device. The output of the voltage regulator is a little less than 5 volts. I don't know the model number. ali express microcontroller. It uses pic16f628A. Display # is 3561aS-1. I am using linux mint cinnamon 21.3 virginia. I want to install the required software on my computer as seen on the internet to program IT and buy the PICKit 3 programmer for $25. but somehow I feel things will go wrong. The data sheet it came with is unclear and I can't make out the schematic. I want to get this working and any advice would be appreciated.

 

If you bought this as a kit, one would have to assume that the MCU is already programmed.
Did the instructions show how the display is supposed to be oriented?
If the photo shows that the decimal points are towards the top then that is the way it is supposed to be.

 

But the silkscreen shows the dots at the bottom. So it's a 50/50 guess, but I'd suspect the silkscreen is more likely to be correct than a picture of one that someone slapped together just for a picture...

 

Check the pinout of the display. Determine if it is common anode or common cathode and check that the common pin is correctly connected.

 

But the silkscreen shows the dots at the bottom. So it's a 50/50 guess, but I'd suspect the silkscreen is more likely to be correct than a picture of one that someone slapped together just for a picture...

I agree.

 

Your link is to a frequency counter module? Yes, it's a kit. I assume a turn key ready to use frequency counter once you assemble it. So what are you asking or looking to do? I see no need to program anything?

Ron

 

Your link is to a frequency counter module? Yes, it's a kit. I assume a turn key ready to use frequency counter once you assemble it. So what are you asking or looking to do? I see no need to program anything?

Ron

Well if there's no need to program anything I feel better because I don't have the software or the hardware to program it

 

Check the pinout of the display. Determine if it is common anode or common cathode and check that the common pin is correctly connected.

There's a little less than -5 v at the cathodes of the displays compared to the positive supply. It's common cathodes.

 

If you bought this as a kit, one would have to assume that the MCU is already programmed.
Did the instructions show how the display is supposed to be oriented?
If the photo shows that the decimal points are towards the top then that is the way it is supposed to be.

The circuit board silkscreen shows the decimal points to be on the bottom and that's how I soldered it, not according to the picture on the website.