RP2040 Dual core ARM Cortex-M0 Microcontroller QFN56

RP2040 Chip features:

• Dual ARM Cortex-M0+ @ 133MHz
• 264kB on-chip SRAM in six independent banks
• Support for up to 16MB of off-chip Flash memory via dedicated QSPI bus
• DMA controller
• Fully-connected AHB crossbar
• Interpolator and integer divider peripherals
• On-chip programmable LDO to generate core voltage
• 2 on-chip PLLs to generate USB and core clocks
• 30 GPIO pins, 4 of which can be used as analog inputs
• Peripherals
  • 2 UARTs
  • 2 SPI controllers
  • 2 I2C controllers
  • 16 PWM channels
  • USB 1.1 controller and PHY, with host and device support
  • 8 PIO state machines

Inside the RP2040 is a 'permanent ROM' USB UF2 bootloader. What that means is when you want to program new firmware, you can hold down the BOOTSEL button while plugging it into USB (or pulling down the RUN/Reset pin to ground) and it will appear as a USB disk drive you can drag the firmware onto. Just note you don't double-click reset, instead hold down BOOTSEL during boot to enter the bootloader!

The RP2040 is a powerful chip, which has the clock speed of (SAMD51), and two cores that are equivalent to M0 (SAMD21). Since it is an M0 chip, it does not have a floating point unit or DSP hardware support - so if you're doing something with heavy floating point math, it will be done in software and thus not as fast as an M4. For many other computational tasks, you'll get close-to-M4 speeds!

For peripherals, there are two I2C controllers, two SPI controllers, and two UARTs that are multiplexed across the GPIO - check the pinout for what pins can be set to which. There are 16 PWM channels, each pin has a channel it can be set to (ditto on the pinout).

You'll note there's no I2S peripheral, or SDIO, or camera, what's up with that? Well instead of having specific hardware support for serial-data-like peripherals like these, the RP2040 comes with the PIO state machine system which is a unique and powerful way to create custom hardware logic and data processing blocks that run on their own without taking up a CPU. For example, NeoPixels - often we bitbang the timing-specific protocol for these LEDs. For the RP2040, we instead use PIO object that reads in the data buffer and clocks out the right bitstream with perfect accuracy. Same with I2S audio in or out, LED matrix displays, 8-bit or SPI based TFTs, even VGA! In MicroPython and CircuitPython you can create PIO control commands to script the peripheral and load it in at runtime. There are 2 PIO peripherals with 4 state machines each.

While the RP2040 has lots of onboard RAM (264KB), it does not have built-in FLASH memory. Instead, that is provided by the external QSPI flash chip. You will need to provide external FLASH memory using QSPI NOR memory. The flash chip is shared between the program it's running and any file storage used by MicroPython or CircuitPython.