.. index rpi pico, rp2040, mandlebrot, rpi pico:pinouts

.. _rpi-pico:

Rpi Pico Board with RP2040 MCU
==============================
The RP2040 has 264KB of onboard RAM, FLASH is external QSPI.

.. image:: rpi-pico/pinouts.jpg


RP2040 Negatives
----------------
Why I don't use this MCU

1. It has no Flash. External SPI nust be used which raises the BOM cost and complexity, plus SPI Flash is slow.
2. RTC: One of the flaws in the RP2040's design is that its RTC has no ability to take battery backup.
3. RTC: The time is always lost on mcu reset.
4. ADC: Due to a silicon design problem, it has a lot of noise which reduces the effectice resolution to 8 bits
5. VREF: there is no hi accuracy VREF on the chip
6. Watchdog: is timing out in half the specified time
   
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

.. _pico-official-release:

Mecrisp Stellaris Pico 
----------------------
Official release. It's a port of Mecrisp-Stellaris and is much the same, hardware differences excepting. Lots more information in the tarball below.

* Serial terminal on UART0
* 115200 Baud 8N1
* TX - pin 1
* RX - pin 2

https://sourceforge.net/projects/mecrisp/files/mecrisp-stellaris-2.5.6.tar.gz


.. _2040-mandlebrot:

The Pico Mandlebrot Challenge
-----------------------------

.. note:: New Release @ 4 Mar 2021. Now with Mandlebrot and Tricorn Set plus a breathing LED cosine effect while waiting for keypress. Still in only 252 Bytes !

https://sourceforge.net/projects/mecrisp-stellaris-folkdoc/files/2021_03_01_mandelboot.tar.gz

* This bootable binary is only  **252 Bytes!** can you make a smaller one ?

* Serial terminal on UART0
* 115200 Baud 8N1
* TX - pin 1
* RX - pin 2

.. image:: rpi-pico/mandlebrot/mandleboot-dual.jpg