HS32 Core RTL Repository

Table of Contents

• Table of Contents
• Getting started
• Preparing the devboard
• Uploading prebuilt firmware
• Regenerating the BRAM firmware
• Connecting to UART with an Arduino

Getting started

Note: If you're only interested in uploading code, you do not need to setup and install the RTL toolchain.

See HOWTO.md for more details on setting up your environment.

Build configurations (Verilog defines):

• SOC Compile with internal BRAM memory interface instead
• SIM Compile for simulations
• PROG Compile for SRAM programmer

Preparing the dev board

• Ensure the FPGA is socketed and properly connected.
• Ensure all power rails measure at the correct voltage.
• Solder a jumper wire from MISO to the BHE# pad
• Beware, the UART RX and TX pins run at 3.3V instead of 5V. The FPGA is NOT 5V tolerant.

Uploading prebuilt firmware

...

Regenerating the BRAM firmware

Let's see how you would run and upload your blinky program using VSCode.

For this, you need to have the RTL toolchain installed

First, we need to generate the bench/bram0.hex to bram4.hex files. Use asm.js to select from a list of premade programs. Here, we will select "blinky":

node build/asm firmware/blinky.asm -fhex -o bench/

Next, run the Build All task and select SOC to configure the project for our dev board. Finally, plug in the dev board and run the Upload task.

Connecting to UART with an Arduino

For a UART connection, you can use an Arduino and a level shifter. For this example, we will use the 74LS245 bus transceiver as the level shifter.

Before you begin, ensure you read the datasheet pinout here

Ensure you have a 3.3V supply (the dev board's 3.3V supply should be fine).

• Connect DIR to GND.
• Connect OE# to GND.
• Connect VCC and GND to 3.3V and ground, respectively.

Here, the A-side will be 3.3V output, and the B-side will be 5V-tolerant input. Thus,

• Connect A1 to dev board RX and B1 to Arduino PIN X
• Connect B2 to dev board TX and A2 to Arduino PIN Y

Keep note of what X and Y are (I chose 3 and 2). Make sure you don't use the dedicated serial pins 0 and 1 on the UNO and similar pins on other boards.

Before you continue, ensure the output levels are correct or you will fry the FPGA.

We will use the Arduino to pass through serial connections:

#include <SoftwareSerial.h>

// Our side's RX, TX (which is TX, RX on the devboard)
SoftwareSerial devSerial(Y, X);

void setup() {
    Serial.begin(9600);
    while(!Serial);
    devSerial.begin(9600);
}

void loop() {
    if(devSerial.available())
        Serial.write(devSerial.read());
    if(Serial.available())
        devSerial.write(Serial.read());
}

Docker Setup

./docker_build

Test: ./dev_docker_run bash

exit