OldWyk

⚠️ Before connecting the Hifive1 make sure that the IOREF jumper on it is set to 3.3V

Wiring

5 wires of the OldWyk SPI interface have to be connected to the Hifive1: GND, SCLK, MISO, MOSI, and CS. The picture below shows where these wires have to be connected to the Hifive1. The pinout of the SPI slave of the OldWyk PCB can be found on the backside of the PCB.

Testing if OldWyk is alive

Check oldwyk-micropython-shell to find the repository containing the micropython firmware, that runs on the HiFive1 if you need to build it yourself.

Connect to the micropython shell on the HiFive 1:

$ screen /dev/ttyUSB1 115200

If you hit ENTER you should see a python shell:

>>>

Now import pyb and create a PULPINO object:

>>> import pyb
>>> pulpino = pyb.PULPINO()

SPI Slave test

To check if it is working, reset pulpino:

>>> pulpino.reset()

This will test if the SPI slave of OldWyk is working. If something is wrong you will see:

Error can't write reg1 of SPI-Slave>>>

LED Blink test

One LED is connected to GPIO 10. To make it blink we first set the GPIO to output (0 means input, 1 means output):

>>> pulpino.gpio_dir(10, 1)

Now we can turn on the LED:

>>> pulpino.gpio_set(10, 1)

You should now see LED D2 turn on.

Raw SPI bus access

To write raw SPI messages, we first need to create a SPI object

>>> spi = pyb.SPI(7, 2000000, 0, 0)

The parameters of the function are pyb.SPI(CS_PIN, MAX_SCK_FREQ, CPOL, CPHA). Now we can use spi.write_mem(ADDR, VALUE) and value = spi.read_mem(ADDR) to read and write anything to the bus.

For example to toggle the LED as done above:

>>> spi = pyb.SPI(7, 2000000, 0, 0)
>>> spi.write_mem(0x1A101000, (1 << 10))
>>> spi.write_mem(0x1A101008, (1 << 10))
>>> spi.write_mem(0x1A101008, 0)

The memory addresses for the GPIOs can be found in the pulpino datasheet

Building toolchain

Prerequisites

Ubuntu

$ sudo apt-get install autoconf automake autotools-dev curl python3 libmpc-dev libmpfr-dev libgmp-dev gawk build-essential bison flex texinfo gperf libtool patchutils bc zlib1g-dev libexpat-dev cmake

Redhat

$ sudo yum install autoconf automake python3 libmpc-devel mpfr-devel gmp-devel gawk  bison flex texinfo patchutils gcc gcc-c++ zlib-devel expat-devel cmake

Archlinux

$ pacman -Syyu autoconf automake curl python3 mpc mpfr gmp gawk base-devel bison flex texinfo gperf libtool patchutils bc zlib expat cmake

Installation

Running

$ make tools

will install the toolchain to prefix/bin

Building pulpino software

All software projects are in the sw/apps folder. If you want to build the software in sw/apps/helloworld then run

$ PROGRAM=helloworld make software

Uploading the sofware to the Arty 35 FPGA running pulpino

If you want to upload the project helloworld then run

$ PROGRAM=helloworld make upload