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Project Description

DSP_ICE is an ICE40-8K FPGA dev system that has been developed using gcc and Project Icestorm toolchains. The hardware has been fully tested except for the PDM microphone. Firmware/HDL examples are provided to test the hardware, including an 8-channel, multi-waveform audio synthesizer and peak amplitude, frequency measurement via CMSIS DSP FFT functions utilizing the LTC1420 ADC expansion module.

Why Develop Another ICE40 Dev Board?

DSP ICE was developed because other boards didn't have all the features desired. The ultimate goal is to develop an SDR with swappable analog/RF front-ends. Desired features that drove the development were:
1) 10/100 Ethernet
2) 8K ICE 40 device that could be done with 5mil spaced, 4-layer pcb
3) I2S audio output
4) STM32F4 device that is foot-print compatible with F7 and H7 series for future
5) 16-bit FSMC memory-bus interface between the MCU and FPGA
6) Low-noise power supplies with plenty of current for expansion modules
7) Plenty of expansion I/O pins designed to utilize upper limits on frequency with ICE40

8-channel audio synth test.mp3 audio output from example audio-synth implemented in Verilog


STM32F417 MCU (upgradable with drop-in for F7 and H7 series up to 400 MHz)
ICE40HX8K-CT256 FPGA (largest ICE40 device available)
16-Bit FSMC interface between MCU <-> FPGA. Interface clock is running @ 80 MHz
10-100 Mbps Ethernet interface (firmware includes iperf3 server for testing bandwidth)
ST-Link programming header (can use STM32F4-Discovery as a programming device)
I2S Audio interface (firmware includes example of 8-channel audio synth with sawtooth, pulse, noise waveforms and a song playback via I2S)
4 PMOD-Like ports (include 5V and 3.3V and 8 I/O pins x 4)
USB FTDI-based serial interface (update 8/13/2017 firmware to test the uart interface has been added)
40 MHz TCXO crystal driving both FPGA and MCU (MCU clock div/2)

Verilog Source Is Here

DSP ICE MCU 16-bit Memory-Mapped FPGA registers
0x60000000   spi1_ctrl
0x60000002   spi1_data_in
0x60000004   spi1_data_out
0x60000006   spi1_cs_ctrl

0x60000008 spi2_ctrl 0x6000000a spi2_data_in 0x6000000c spi2_data_out 0x6000000e spi2_cs_ctrl

0x60000010 adc_data (LTC1420 hw module, read-only, bit0 is OF)

0x60001000 audio_ctrl 0x60001002 left_sample 0x60001004 right_sample 0x60001006 tone1_freq 0x60001008 tone2_freq 0x6000100a tone3_freq 0x6000100c tone4_freq 0x6000100e tone5_freq 0x60001010 tone6_freq 0x60001012 tone7_freq 0x60001014 tone8_freq 0x60001016 waveform_ctrl

0x6000f000 16-bit random number (ro)

PCB Design
4 layers
Designed for OSH Park 4 layer service. (5 mil spacing)
Have assembled 4 boards without any connectivity issues on the 256-pin BGA

Left To Do
The PDM michrophone has not been tested yet due to trouble getting the part.

Digikey has the part in stock, but Cirrus Logic will not allow them to sell
it to certain individuals including the author of this project. There were
no further explanations from Cirrus Logic.

Building The Firmware

Instructions (tested on Debian 8 system)

1) download GNU ARM Embedded Toolchain from here: 

The test firmare was compiled with version:

2) *edit the makedefs_fp and change PRE_PREFIX to point to the absolute path of
the toolchain directory *optionally,  move the uncompressed toolchain folder to
the project folder and rename to gnu_arm_toolchain

3) From the project directory, In order to re-build the FPGA binary image, type
'sh'  (requires that Project Icestorm tools are installed)

  yosys  (synthesis tool)
  ice-tools  (tools for maniuplating text/binaries and programming dev boards) 
  arache-pnr  (place-and-route) 

  Note:  The fpga binary configuration image will be compressed and converted
to a header file for inclusion to the MCU firmware image:  fpga_image.h The
compressed image in fpga_image.h will be included in fpga.c on the next mcu
firmware build  (step 4) The MCU uncompresses and transfers the fpga config
image during startup.

4) From the project directory, type 'make clean' followed by  'make' The
resulting binary will be copied to /tmp folder and also the build_image folder
in the current project directory Note: the prototypes in protos can be
re-generated with 'make genprotos' if cfunctions is installed.

5) An ST-Link programmer can be used to load the resulting binary
(main_image_0x8000000.bin) to address 0x8000000

   A $15 STM32F4 Discovery board with the jumpers set to "ST Link"  (pulled
off) and a straight-thru, 6-pin 0.1" pitch cable will work.

   Follow instructions for compiling OpenOCD

   start the debugger:  'sudo src/openocd -s tcl -f tcl/board/stm32f4discovery.cfg'

   'telnet localhost 4444'
    > reset halt
    > flash write_image erase build_image/main_image_0x8000000.bin 0x8000000

6) Test the hardware.
   telnet   (default ip address.  edit this in config.c)
Connected to
Escape character is '^]'.

Connected To STM32F417 Running @ 168 MHz
DSP_Ice$ help

Available commands:


DSP_Ice$ testadc
Example measurement of 500 KHz sine wave, 100mVpp utilize LTC1420 ADC HW module
This example utilizes the CMSIS DSP Co-Processor functions of the MCU for FFT calcs.
Using DMA to transfer ADC results from FPGA BRAM would dramatically improve sample rate
peak signal 502675.781 Hz,  0.107 Volts p-p, elapsed time 3.51 ms  
[see fft plot 500khz, 100mV p-p] 
[see fft plot 325Khz, 3500mV p-p] 
[see time-domain plot 500khz, 3500mV p-p] 
DSP_Ice$ testmem   (this tests the 16-bit FSMC memmory-mapped, MCU<->FPGA interface)

x100x (FPGA D-REG), 4015677440 bytes r/w random access, current vals: f3e7,f3e7, errors: 0
0x100x (FPGA D-REG), 4015685632 bytes r/w random access, current vals: 69c4,69c4, errors: 0
0x100x (FPGA D-REG), 4015693824 bytes r/w random access, current vals: af9a,af9a, errors: 0
0x100x (FPGA D-REG), 4015702016 bytes r/w random access, current vals: bc6a,bc6a, errors: 0
0x100x (FPGA D-REG), 4015710208 bytes r/w random access, current vals: 8732,8732, errors: 0
0x100x (FPGA D-REG), 4015718400 bytes r/w random access, current vals: 06f4,06f4, errors: 0
0x100x (FPGA D-REG), 4015726592 bytes r/w random access, current vals: 32af,32af, errors: 0

DSP_Ice$ sh

Connecting to host, port 5201
[  4] local port 45612 connected to port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec  8.91 MBytes  74.7 Mbits/sec    0   14.3 KBytes       
[  4]   1.00-2.00   sec  8.88 MBytes  74.5 Mbits/sec    0   14.3 KBytes       
[  4]   2.00-3.00   sec  8.86 MBytes  74.3 Mbits/sec    0   14.3 KBytes       
[  4]   3.00-4.00   sec  8.86 MBytes  74.3 Mbits/sec    0   14.3 KBytes       
[  4]   4.00-5.00   sec  8.88 MBytes  74.5 Mbits/sec    0   14.3 KBytes       
[  4]   5.00-6.00   sec  8.87 MBytes  74.4 Mbits/sec    0   14.3 KBytes       
[  4]   6.00-7.00   sec  8.86 MBytes  74.3 Mbits/sec    0   14.3 KBytes       
[  4]   7.00-8.00   sec  8.86 MBytes  74.3 Mbits/sec    0   14.3 KBytes       
[  4]   8.00-9.00   sec  8.86 MBytes  74.3 Mbits/sec    0   14.3 KBytes       

iperf Done.

DSP_Ice$ testsnd   (song playback via 8-channel audio synth implemented on fpga)

change instrument: ch: 0,  instr: 29, mask: 5555
chan: 0, freq: 554
change instrument: ch: 1,  instr: 37, mask: 5555
chan: 1, freq: 92
change instrument: ch: 2,  instr: 16, mask: 5575
chan: 2, freq: 233
change instrument: ch: 3,  instr: 29, mask: 5575
chan: 3, freq: 370
change instrument: ch: 4,  instr: 16, mask: 5775
chan: 4, freq: 131
change instrument: ch: 5,  instr: 16, mask: 5f75
chan: 5, freq: 131
duration: 91
duration: 91
chan: 0, freq: 494
chan: 3, freq: 330
duration: 91
duration: 91
chan: 2, freq: 208
chan: 0, freq: 554
chan: 3, freq: 370
duration: 91
duration: 91
chan: 0, freq: 494
chan: 3, freq: 330
duration: 91
duration: 91
chan: 0, freq: 554
chan: 3, freq: 370
duration: 91
duration: 91

Images Of LTC1420 HW Module and PCB cad rendering


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ICE40 8K FPGA / STM32F4 development system







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