Is there a high-GPIO count PIC with through hole leads, instead of SMD?

[PomPom]

I want to control a matrix of LEDs for a little light show project. I want to run a grid of 18x18 LEDs and need 36+ IO but can only find that as an SMD package.

I don't know if it's even possible to place SMD components down and hook them up to all my discrete LEDs, so I'm wondering if there is a through hole solution.

And on that note, is there a place to buy these through hole components for a reasonable price? The distributors I've looked at all seem to be for high-power applications--where did my school get the cheap through hole FETS and OPAMPS that they supply us with?

Thank you,

Roman

 

[bigdogguru]

The 40 DIP package is the largest through hole package available from Microchip.

One option is the use of external Shift Registers, like the 74HC595, examples and PIC source code are available in the following thread:

Questions bout shiftregisters (74HC575, 74HC597)


Another is the use of I2C/SPI Port Expanders like the MCP23017 or MCP23S17.

Both solutions are cascadable, allowing the use of multi devices to provide high I/O pin counts.


BigDog

 

[PomPom]

To be honest I don't understand either of those. The first seems taking parallel IOs, turning them into a few serial streams, and then back to parallel? I'm pretty new to this, could you please explain it in simpler terms?

thank you for your response

 

[bigdogguru]

Actually I was referring to the 74HC595, which is also covered later in the thread.

Essentially, the device takes serial data, from the SPI port or general I/O pins, and outputs the data in a parallel format.

Can you move over? The 74HC595 8 bit shift register

Using shift registers to extend the microcontroller I/O


BigDog

 

[PomPom]

So this way I could multiply my number of outputs by 8 (for each shift register i use?) I send, eg, 10101010, and it will become 8 separate outputs. Then my PIC would have to be 8 times faster than I had planned, right?

 

[bigdogguru]

So this way I could multiply my number of outputs by 8 (for each shift register i use?) I send, eg, 10101010, and it will become 8 separate outputs.

Yes, correct and you can cascade several shift registers to create a large group of outputs.

Then my PIC would have to be 8 times faster than I had planned, right?

It is difficult to answer that question with certainty without examining your design requirements and your code.

The SPI port is capable of 10MHz performance on most PICs and essentially automates the process to a few lines of Assembly or C statements.


BigDog

 

[doraemon]

Hello!

Maybe one way to explore is to find an adaptor board.
I have googled this : https://www.futurlec.com/SMD_Adapters.shtml

Dora.