doppler4arduino
Doppler - CortexM4 meets FPGA
- arduino compatible board
- 120Mhz ARM Cortex M4 MCU 1MB Flash (samd51g19a) with FPU
- FPGA 5000 LUT, 1MBit RAM, 6 DSP Cores,OSC, PLL (Lattice ice40up5k)
- breadboard friendly (DIL48)
- micro usb
- power over USB or external via pin headers
- VCC 3.5V …. 5.5V
- all GPIO Pins are 3.3V
- 1 led connected to samd51
- 4 x 4 LED Matrix (connected on fpga)
- 2 Custom Buttons (connected on fpga)
- ARef Solder Jumper
- I2C (need external pullup), SPI, QSPI Pins
- 2 DAC pins, 10 ADC pins
- full opensource toolchain
- SWD programming pin headers
- double press reset to enter the bootloader
- uf2 bootloader with Firmwareupload via simple USB stick mode
Builds based on this repo: https://github.com/noscene/ArduinoCore-samd
Setup
First need install the arduino ide from
- https://www.arduino.cc/en/Main/Software
then add board URLs (comma separated):
- https://adafruit.github.io/arduino-board-index/package_adafruit_index.json,
- https://noscene.github.io/doppler4arduino/package_doppler_index.json
go to boardmanager
install both boards
select the Doppler Board
select USB Port
Board Layout and PINs
/* DOPPLER-Board-Layout:
* ---------------- FPGA Pins ------------------
* DAC1 SCK MOSI DAC0 LedR LedG LedB CT1 CP0
* DIL Pin 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25
* |--O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O---|
* name | VIN 5V 3.3V A10 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 GND R2 R1 R0 F14 F13 F12 F11 F10 F9 |
* alt | VIN 5V 3.3V PA11 PA10 PA09 PA08 PA07 PA06 PA05 PA04 PB09 PB08 PA02 GND 41 40 39 38 37 36 35 34 32 |
* | ö ö ö ö |
* | ö ö ö ö |BTN:S1| |
* | USB DOPPLER: SamD51 <- SPI -> icE40 |BTN:RESET| ö ö ö ö |
* | ö ö ö ö |BTN:S2| |
* | |
* alt | GND PA13 PA12 PB11 PA14 PA15 PB10 PA31 PA30 RES PA19 PA20 PA21 PA22 3.3V 11 12 13 18 19 20 21 23 25 |
* name | GND 0 1 2 3 4 5 6 7 8 9 3.3V F0 F1 F2 F3 F4 F5 F6 F7 F8 |
* L--O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O----O---|
* DIL Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
* SCL SDA MISO SS SWD SWC RES CT0 CP0
* -- I2C-- --- SWD --- ----- Shared ----- ---------------- FPGA Pins ------------------
*/
Examples
Blink on board LED
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(LED_BUILTIN, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
fast write 2 DAC Channels on A0 and A4 (PA02+PA05)
void setup() {
// put your setup code here, to run once:
pinMode(PIN_DAC0,OUTPUT);
pinMode(PIN_DAC1,OUTPUT);
dacInit();
}
void loop() {
// put your main code here, to run repeatedly:
static uint16_t left = 0;
static uint16_t right = 0;
left+=256;
right-=256;
dacWrite(left,right);
}
FPGA demo set 4x4 LED Matrix
see https://github.com/noscene/Doppler_FPGA_Firmware for make bitstream from verilog
#include <ICEClass.h>
ICEClass ice40;
uint16_t leds = 1;
void setup() {
// put your setup code here, to run once:
ice40.upload(); // Upload BitStream Firmware to FPGA -> see variant.h
delay(100);
// start SPI runtime Link to FPGA
ice40.initSPI();
}
void loop() {
// put your main code here, to run repeatedly:
ice40.sendSPI16(leds );
leds = leds << 1;
if(leds==0){
leds=1;
}
delay(100);
}
Show hex chars on 4x4 matrix
#include <ICEClass.h>
ICEClass ice40;
uint16_t hexmapFont[16] = { 0xF99F,0xF22F,0xF42F,0xF17F,0x1F99,0x7F8F,0xF9F8,0x111F,
0x7DBE,0x1F9F,0x9F9F,0xADAC,0xF88F,0xE99E,0xF8EF,0x8E8F };
void setup() { // put your setup code here, to run once:
ice40.upload(); // Upload BitStream Firmware to FPGA -> see variant.h
delay(100);
ice40.initSPI(); // start SPI runtime Link to FPGA
}
void loop() { // put your main code here, to run repeatedly:
for(int i = 0 ; i < 16 ; i++){
ice40.sendSPI16(hexmapFont[i] );
delay(800);
}
}
Create second I2C Bus as Wire1 on pins A7+A8 and scan the bus
see https://learn.adafruit.com/using-atsamd21-sercom-to-add-more-spi-i2c-serial-ports/creating-a-new-wire how to handle sercoms
#include <Wire.h>
#include "wiring_private.h" // pinPeripheral() function
TwoWire Wire1(&sercom0, A7, A8); // create new Wire Port
void setup() {
// put your setup code here, to run once:
Wire1.begin(); // set pinPeripheral after this line!!!
pinPeripheral(A7, PIO_SERCOM); // assign SDA
pinPeripheral(A8, PIO_SERCOM); // assign SDC
Serial.begin(9600);
Serial.println("\nI2C Scanner");
}
void loop() {
// put your main code here, to run repeatedly:
byte error, address;
int nDevices;
Serial.println("Scanning...");
nDevices = 0;
for(address = 1; address < 127; address++ ) {
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire1.beginTransmission(address);
error = Wire1.endTransmission();
Wire1.requestFrom(address,2);
if (error == 0) {
Serial.print("I2C device found at address 0x");
if (address<16)
Serial.print("0");
Serial.print(address,HEX);
Serial.println(" !");
nDevices++;
} else if (error==4) {
Serial.print("Unknow error at address 0x");
if (address<16)
Serial.print("0");
Serial.println(address,HEX);
}
}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done, if find on each addr -> check pullups! \n");
delay(5000); // wait 5 seconds for next scan
}
Create UART RX,TX Serial2 on pins A7+A8
see https://learn.adafruit.com/using-atsamd21-sercom-to-add-more-spi-i2c-serial-ports/creating-a-new-serial how to handle sercoms
// Create Serial2 instance
#include "wiring_private.h" // pinPeripheral() function
Uart Serial2 (&sercom0, A7, A8, SERCOM_RX_PAD_1, UART_TX_PAD_0);
void SERCOM0_0_Handler() { Serial2.IrqHandler(); }
void SERCOM0_1_Handler() { Serial2.IrqHandler(); }
void SERCOM0_2_Handler() { Serial2.IrqHandler(); }
void SERCOM0_3_Handler() { Serial2.IrqHandler(); }
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
Serial2.begin(9600);
pinPeripheral(A7, PIO_SERCOM); // TX
pinPeripheral(A8, PIO_SERCOM); // RX
}
uint8_t i=0;
void loop() {
Serial.print(i);
Serial2.write(i++);
if (Serial2.available()) {
Serial.print(" -> 0x"); Serial.print(Serial2.read(), HEX);
}
Serial.println();
delay(500);
}
Performance
Classic ArduinoStyle vs direct Register Access
void setup() {
pinMode(0,OUTPUT); // PA13
digitalWrite(0,true);
}
// direct SAMD51 register access PA13
void loop() {
while(1){
PORT->Group[PORTA].OUTCLR.reg = 1ul << 13; // this part generate 30Mhz so it looks like this part need 2 cpu cycles for each pin change
PORT->Group[PORTA].OUTSET.reg = 1ul << 13; // this part generate 30Mhz
}
}
// classic way but not realy fast
void loop_not_very_fast() {
digitalWrite(0,true); // this part generate 0.5 Mhz
digitalWrite(0,false); // this part generate 0.5 Mhz
}