Arduino core extensions for FPGA-based 32-bit MIPS and RISC-V soft CPU cores (f32c).

We have preliminary Boards Manager support. In File->Preferences->Additional Boards Manager URLs enter:

http://www.nxlab.fer.hr/fpgarduino/package_f32c_core_index.json

Select pull down menu Tools->Board->Board Manager and instal FPGArduino (cca 100MB).

Upgrading

Before upgrading to new version, boards manager cache has to be manually removed by deleting hidden directory 'packages'. If install is attempted with old cache, it will fail with CRC error.

windows cache: .../Arduino15/staging/packages (use Find files)
linux cache: ~/.arduino15/staging/packages

Delete packages directory, then remove/install from boards manager.

To upload some bitstreams OpenOCD may complain about libusb drivers. libusb is common on linux. To install libusb on windows, easiest way is with Zadig http://zadig.akeo.ie Options->List All Devices Select usb serial device, select driver WinUSB and click install.

Manual install: Copy or symlink this to existing arduino directory (versions 1.6.0 and newer), close the Arduino IDE, open it again and new FPGA boards, progammers and examples should appear under pull down menus:

tools->boards->...new mips and riscv boards..

tools->programmers->...ujprog openocd etc...

file->examples->f32c->...

file->examples->...RCswitch...Adafruit GFX/SSD1306..

We had to do small modifications of original examples for AVR-specific or hardware-dependent stuff in order to get them running out of the box on f32c.

Source tree arduino/hardware/fpga contains complete arduino core for unified MIPS and RISC-V achitecture support. Only this directory is needed to be copied to your existing arduino-1.6.x tree. Core can work alone without libraries and examples.

The core comes without GCC for MIPS/RISC-V and tools to upload binary and FPGA bitstreams (ujprog, openocd, JTAGs).

Precompiled binaries for linux and windows with GCC MIPS and RISC-V can be fetched and installed separately, see http://www.nxlab.fer.hr/fpgarduino for further instructions.

There are some short scripts and patches to build GCC from source in https://github.com/f32c/f32c/tree/master/src/compiler

Blink led :)

Serial (over usb-ttl adapter, some boards need it external)

Timer (millis(), micros() - 32-bit CPU core clock counter, glitch-free, good for realtime)

GPIO (digitalWrite(), digitalRead())

Interrupts (MIPS only, attachInterrupt() gpio rising/falling edge, timer)

PWM (analogWrite(), analogWriteResolution(), analogWriteFrequency())

Fade (PWM) works on 2 output pins (LEDs).

Software SPI (bitbang, Adafruit OLED library)

Hardware SPI (SD card library)

Software I2C in master mode (SoftwareWire library)

OLED displays SSD1306 compatible (Adafruit SSD1306 library, SPI and I2C)

PID (Proportional-Integral-Derivative controller, fast response, hardware math accellerated, tested on high speed DC motors with encoders)

433.92 MHz transmitter (RCswitch library, Home automation, Remote relays, Garage doors).

FM RDS transmitter 87-108 MHz (RDS message displayed on radio, but PCM sound supported only on ULX2S)

RHT11 Temperature/Humitidy sensors have been reported to work.

SDRAM works for data with d-cache. SDRAM works also for instructions without i-cache (slow). Work is currently in progress to fix i-cache and make full functional bus arbiter for SDRAM.

VGA and HDMI outputs work but only as proof of concept because BRAM content is displayed which is very small, few KB typical. When multiport synchronous RAM bus access from VGA/HDMI to SDRAM is ready then some better HDMI picture might be seen.

1MB SRAM using both 8-bit ports works at 81.25 MHz CPU clock, widely tested.

TV Framebuffer with composite video output displaying SRAM content

PCM sound (depends on DMA). PCM outputs PWM for headphones and FM for reception on 87-108 MHz radio.

Text-to-Speech library TTS. (depends on PCM) TTS library could be converted to use a simple tongenerator then it will not depend on PCM)

DCF77 transmitter (depends on PCM) A proof of concept to adjust longwave RF clocks.

Analog inputs (cheap FPGA used to not to have ADC, please contribute some code for new hardware...)

Hardware I2C slave is not planned soon, as f32c is expected to be an I2C master in most cases.

There's SoftwareWire I2C master which works because F32C is fast enough and has high resolution 32-bit timer.