Hi Everybody,
in my current project I want to use a RaspBerry Pi pico RP2040 to communicate with another RP2040 over CAN-BUS using the CAN-BUS-modul with the MCP2515-Chip.
So I looked up the RP2040-Pinout. I found one at adafruit
So what does this mean?
Are the pins used for SPI configurable?
If yes what are the default SPI-pins and how can the default-configuration be changed?
best regards Stefan
Yes, it's common practice for processors to have several functions multiplexed on each physical pin.
I've never used that processor. But I can think of three places to look:
Just looking at the prototype for the constructor in SPI.h:
class MbedSPI : public SPIClass
{
public:
MbedSPI(int miso, int mosi, int sck);
MbedSPI(PinName miso, PinName mosi, PinName sck);
And here's you see the instances declared:
#if SPI_HOWMANY > 0
extern arduino::MbedSPI SPI;
#endif
#if SPI_HOWMANY > 1
#ifdef SPI1
#undef SPI1
#endif
extern arduino::MbedSPI SPI1;
#endif
first I thought OMG diggin' down all the rabbit-hole of analysing the corefiles.
Did nobody ever before wrote a demo-code?
Sure when arduino-IDE ( I am using the old version 1.8.19) is adjusted to RaspBerry Pi Pico the examples show
File - examples - examples from custom libraries - ACAN2515 - LoopBasicDemoRaspBerryPiPico
And indeed there is a comment
// The Pico has two SPI peripherals, SPI and SPI1. Either (or both) can be used.
// The are no default pin assignments so they must be set explicitly.
// Testing was done with Earle Philhower's arduino-pico core:
// https://github.com/earlephilhower/arduino-pico
though this comment tells not everything that is important:
from this comment I concluded that almost any pin be used and choosed them
"randomly" This resulted in the pico AND Arduino-IDE beeing locked up!
I had to use the task-manager to kill all IDE-processes to make the IDE work again.
So I expanded the comment to explicitly say what is important
// The Pico has two SPI peripherals, SPI-0 and SPI-1. Either (or both) can be used.
// The are no default pin assignments so they must be set explicitly.
// According to the RP2040 data sheet, section 1.4.3 ”GPIO Functions” page 13,
// you have the following choices for SPI pins:
// SPI-0_SCK IO-Pins: 2, 6, 18, 22
// SPI-0_MOSI (SPI0 TX) IO-Pins: 3, 7, 19, 23
// SPI-0_MISO (SPI0 RX) IO-Pins: 0, 4, 16, 20
// SPI-0 CS IO-Pins: 1, 5, 17, 21
// SPI-1_SCK IO-Pins: 10, 14, 26
// SPI-1_MOSI (SPI1 TX) IO-Pins: 11, 15, 27
// SPI-1_MISO (SPI1 RX) IO-Pins: 8, 12, 24, 28
// SPI-1_CS IO-Pins: 9, 13, 25, 29
I found this better and more detailed information in the doc-file of the
ACAN2515.h-library-sub-folder
C:......\libraries\ACAN2515\extras named acan2515.pdf
As much as I appreciate the voluntary work of so many people to create open source software
and I honor this I want to say additionally: improve the documentation
best regards Stefan
connecting a MCP2515 to RP2040 so
// RP2040 RPi PICO connections
// MCP2515 INT to RP2040 GP20
// MCP2515 SCK to RP2040 GP18 SPI0_SCK
// MCP2515 SI to RP2040 GP19 SPI0_TX
// MCP2515 SO to RP2040 GP16 SPI0_RX
// MCP2515 CS to RP2040 GP17 SPI0_CSn
// MCP2515 GND to RP2040 GND
// MCP2515 VCC to RP2040 GP 3.3V
using the 107-arduino-mcp2515 library and running File>Examples>107-arduino-mcp2515>MCP2515_Loopback program I get
RP2040 RPi Pico MCP2515 test loopback
[ 724675] ID 1 DATA[0]
[ 735133] ID 2 DATA[4] CA FE CA FE
[ 745577] ID 3 DATA[8] CA FE CA FE CA FE CA FE
[ 755519] ID 4 DATA[4] 33 0 10 7C
[ 765424] ID 7FF DATA[0]
[ 775812] ID(EXT) 80000000 DATA[0]
[ 786012] ID(EXT) 9FFFFFFF DATA[0]
which correspond to the sCanTestFrame values
Hello @StefanL38 ,
I've started playing with these, I'm using Earle Philhower's core, I think if you use it then you'll find the answer to your questions here:
https://arduino-pico.readthedocs.io/en/latest/
Attached pinout shows which pins are default.
Pico-R3-A4-Pinout.pdf (377.0 KB)
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