all dc/dc converter PCBs are now built using infrared soldering! this results in better alignment of the parts.
Particulary for the diode this is a good improvement. It is rather difficult to mount this part manually.
LED matrix laboratory… In the past years I tried many ideas how to drive LED matrix and 7 segment displays. Transistors, individual resistors, shifting registers, and bus buffers for the sink. Now I had the idea to use a 16F59 directly both for the rows and columns.
Initially there are resistors since the chip can not be programmed at 2 volts or 3 volts, but then the resistors are bypassed.
Today I programmed the 16f59. All the rows and columns are wired directly, the columns are split up using two ports. I even tried 4.0 volts and the LEDs “survived”.
System frequency is 560 kHz. I want to add serial interface, since the 16f59 is not good to programm text scrolling (only 2 stacks).
It works…here the brightness of the LEDs is against the camera flash @ 3 volts. on the backside I have mounted one 16f1824 PCB.
It is more easy to use one 16f59 than 3x shifting registers! And I do not have adapter boards for them or any DIL chips left.
Lots of 16f59 sitting around and I do not have much use for them! Well now I found an application: drive LED matrix!
LED scrolling message- did you program this using old-type 16F PIC? They are not very good for this purpose due to banking and small RAMs. The new 16f1824 is much better: It has 2 FSR’s, and a “linear data memory” as well it can read flash via FSR. programming becomes much more easy.