PMOD-8x7-LEDS-module

PMOD dot matrix module, without external driver chip, can directly use 8 IOs to independently drive up to 56 LEDs
(there are also 0603 and 0805 versions. If 0402 finds it difficult to solder, we may consider making the 0603 and 0805 versions public in the future (relatively) It's too big for the pmod interface, I don't like it very much, but I drew the board through automatic routing)
The final version is "PCB_PMOD-8x7-LEDS_4"!!!
Don't find the wrong pcb file
. It has been verified. There are several drawings below. A circuit diagram, three of which were automatically routed by lceda, and the first one was manually routed by me (I feel that if such a small module does not follow regular wiring, automatic routing is quite worry-free) (three automatically routed PCBs, The schematics were put in the wrong order before, which resulted in the final PCB being prototyped. The first column and the other columns lit up in a different order. In actual use, this is not a big problem (you can directly flip the data in the first column in the code). This problem has been solved. It has been corrected in the manual wiring version)
 
The pin needs to be able to set the mode to a high-impedance IO port (tri-state IO) before it can be used. For FPGA, there are not many problems. The IO of inout is tri-state ( The IO of stm32 is set to the input high-impedance state. This can be easily modified through the register. Later I will design a small board with several pmod interfaces based on stm32f103, so stay tuned). All LEDs are driven by IO The IO port provides current, and there may be certain requirements for the IO current size. I used a 470R resistor as the current limiting resistor. The maximum current of each IO port is about 10ma (theoretical calculation, no actual measurement), which can be replaced according to your own needs. I haven't written the driver code for the current-limiting resistor
 
yet (after all, I haven't drawn a board that can use pmod, I just made some modules first)