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Introduction

A project log for RP2040 : PIO - case study

This is a small research on how to use the Raspberry Pi Pico's PIO module.

NYH-workshopNYH-workshop 02/21/2021 at 03:160 Comments

Like explained in the front page, we all know how to bit-bang, wait and more bit-bang when we have to control something that is not supported in a hardware manner. 

Most of the microcontrollers in the market will have a hardware SPI, I2C and other protocols. This allows users to just simply send and receive the data without a lot of firmware/software intervention. However, some hardware contains custom protocols that demand bit-banging if the microcontroller system doesn't have it. It would be fine if this hardware isn't high speed. What if it needs that high speed? Or what if you need to do a lot of things in between and then also have to bit-bang? When it reaches to this situation, you know it is not going to be pleasant anymore. 


The most fun and strange part about this RP2040 is, this PIO module is going to save the day.

As a summary, from its datasheet:

The programmable input/output block (PIO) is a versatile hardware interface.

It can support a variety of IO standards,
including:
• 8080 and 6800 parallel bus
• I2C
• 3-pin I2S
• SDIO
• SPI, DSPI, QSPI
• UART
• DPI or VGA (via resistor DAC

 You can program this thing to do whatever protocol you wanted, with these precisely timed and deterministic instructions.

In this article, explaining how we can use the PIO module to drive some simple LED/LCD displays.

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