ARC EM Software Development Platform

Overview

The DesignWare® ARC® EM Software Development Platform (SDP) is a flexible platform for rapid software development on ARC EM processors and subsystems. It is intended to accelerate software development and debug of ARC EM processor-based systems for a wide range of ultra-low power embedded applications such as IoT, sensor fusion, and voice applications.

The EM SDP includes an FPGA-based hardware board with commonly used peripherals and interfaces for extensibility. Downloadable platform packages containing different hardware configurations enable the board to be programmed with different ARC EM processors and subsystems. The packages also contain the necessary software configuration information for the toolchain and embARC Open Software Platform. The development platform is supported by Synopsys’ ARC MetaWare Development Toolkit, which includes a compiler, debugger and libraries optimized for maximum performance with minimal code size. The embARC Open Software Platform (OSP), available online from embARC.org, gives developers online access to device drivers, FreeRTOS, middleware and examples that enables them to quickly start software development for their ARC-based embedded systems.

Key Features

• Xilinx Kintex-7 XC7K325T-2FBG676C
• 32 MByte Quad-SPI Flash memory (for configuration and operation)
• USB-JTAG bridge FT2232H
• FPGA configuration through:
  • JTAG
  • SPI Flash memory
• SPI Flash configuration through:
  • JTAG
  • USB
• Connectors
  • Arduino compatible pin headers
  • MicroBUS compatible pin headers
  • 3x Pmod compatible pin headers
  • 50 pin header 2.54mm (40 single-ended IO, 20 differential lanes, variable VCCIO)
  • Mictor Debug connector
  • 10 pin Debug connector 2mm
• 2 x 8 MByte PSRAM IS66WVC4M16EALL
• 32 MByte User Quad-SPI Flash memory
• Micro SDcard Socket
• Wireless module RS9113-NBZ-D1C (Wi-Fi/BT/BLE)
• 3-axis gyroscope, 3-axis accelerometer, 3-axis magnetometer MPU-9250
• Stereo Audio Codec MAX9880A
• 2 x PDM Microphones SPK0641HT4H-1
• 2 x 3.5mm RCA audio jacks (input/output)
• 100MHz User Clock Oscillator SiT8008
• Status LEDs
• Power LED
• 8 x User LEDs
• Reset Buttons
• User Button
• 2 x 4bit User DIP switches
• 12V Power Supply
• 12V fan

Block Diagram

Connecting to the Serial Terminal

Warning

On Linux machines it may be necessary for a user to be in dialout group to successfully connect to a serial terminal. In case of "Permission denied" error try to add a user to the group:

sudo usermod -aG dialout username

Connecting to the board using USB data port allows to connect to the serial terminal over UART. You need to configure these parameters of a serial terminal to interact with the serial port:

• baud-rate 115200
• 8 data bits
• 1 stop Bit

On Windows Putty or any similar software may be used for connecting to the serial terminal. You can find the port number in Device Manager in Ports (COM & LPT) section: USB Serial Port (COMx) where COMx is a value for Serial line field in Putty's. Other parameters may be set Connection → Serial menu.

On Linux minicom or other similar utilities may be used. Here is an example of command line for minicom:

minicom -8 -b 115200 -D /dev/ttyUSB1

After resetting the EM SDP you will see this output of the bootloader:

U-Boot 2020.04 (Sep 09 2022 - 08:54:58 +0200)

CPU:   ARC EM11D v5.6 at 40 MHz
Subsys:ARC Data Fusion IP Subsystem
Model: snps,emsdp
Board: ARC EM Software Development Platform v1.2
DRAM:  16 MiB
PSRAM initialized.
MMC:   mmc0@f0010000: 0
Loading Environment from FAT... MMC: no card present
In:    serial0@f0004000
Out:   serial0@f0004000
Err:   serial0@f0004000
emsdp#

Building and Running Baremetal Applications

EM SDP board is shipped with with FPGA chip. There is a number of ARC EM images available for writing to it. Here is a list of those images and corresponding target options for GCC:

CPU image	GCC targets options
EM11D	-mcpu=em4_fpuda -mmpy-option=6 -mfpu=fpuda_all
EM9D	-mcpu=em4_fpuda -mmpy-option=6 -mfpu=fpuda_all
EM7D	-mcpu=em4_dmips -mno-div-rem -mmpy-option=3 -mfpu=fpuda_all
EM7D ESP	-mcpu=em4_fpuda -mmpy-option=6 -mbarrel-shifter -mfpu=fpuda_all
EM6	-mcpu=em4_dmips -mno-div-rem -mmpy-option=3 -mfpu=fpuda_all
EM5D	-mcpu=em4_fpuda -mmpy-option=6 -mfpu=fpuda_all
EM4	-mcpu=em4_fpuda -mno-div-rem -mmpy-option=3 -mfpu=fpuda_all

In this guide we use EM11D core as an example. Also, the version of the EM SDP firmware is considered to be 1.0 or 1.1.

Consider a simple application with name main.c:

#include <stdio.h>

int main()
{
    printf("Hello, World!\n");
    return 0;
}

Build the application:

arc-elf32-gcc -mcpu=em4_fpuda -mmpy-option=6 -mfpu=fpuda_all \
              -specs=emsdp1.1.specs main.c -o main.elf

-specs=emsdp1.1.specs sets a proper memory map and links the application with additional startup code and UART library for input/output operations.

Here is a list of all available specs files:

Specs file	EM SDP firmware	Description
emsdp1.1.specs	1.0, 1.1	Code and data are placed in ICCM and DCCM
emsdp1.1_ram.specs	1.0, 1.1	Code and data are placed in RAM
emsdp1.2.specs1	1.2	Code and data are placed in ICCM and DCCM
emsdp1.2_ram.specs	1.2	Code and data are placed in RAM

Follow Using OpenOCD guide and start OpenOCD with snps_em_sk_v2.3.cfg configuration file. Here is a possible output:

$ openocd  -f board/snps_em_sk_v2.3.cfg
Open On-Chip Debugger 0.12.0+dev-gffa52f0e0 (2023-08-02-10:41)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : ftdi: if you experience problems at higher adapter clocks, try the command "ftdi tdo_sample_edge falling"
Info : clock speed 10000 kHz
Info : JTAG tap: arc-em.cpu tap/device found: 0x200044b1 (mfg: 0x258 (ARC International), part: 0x0004, ver: 0x2)
Info : starting gdb server for arc-em.cpu on 3333
Info : Listening on port 3333 for gdb connections

Then connect to the server using GDB:

$ arc-elf32-gdb -quiet main.elf
(gdb) target remote :3333

# Increase timeout, because OpenOCD sometimes can be slow
(gdb) set remotetimeout 15

# Load application into target
(gdb) load

# Go to start of main function
(gdb) tbreak main
(gdb) continue

# Resume with usual GDB commands
(gdb) step
(gdb) next

# Go to end of the application
(gdb) tbreak exit
(gdb) continue

# For example, check exit code of application
(gdb) info reg r0

How to Manually Flash a Firmware

You can flash a firmware of ARC CPU manually using Digilent Adept utilities. Firstly, ensure that EM SDP in connected to the host:

$ djtgcfg enum
Found 1 device(s)

Device: JtagSmt1
    Device Transport Type: 00020001 (USB)
    Product Name:          Digilent JTAG-SMT1
    User Name:             JtagSmt1
    Serial Number:         210203826102

Device name for EM SDP is JtagSmt1. Then get a firmware from EM SDP bundle (for example, emsdp_em11d_dfss.bit for EM11D), init the board using init command and program board's FPGA:

$ djtgcfg -d JtagSmt1 init
Initializing scan chain...
Found Device ID: 43651093

Found 1 device(s):
    Device 0: XC7K325T

$ djtgcfg -d JtagSmt1 prog -i 0 -f emsdp_em11d_dfss.bit
Programming device. Do not touch your board. This may take a few minutes...
Programming succeeded.

Useful Links

• ARC EM Software Development Platform - User Guide
• Official Synopsys Page
• embARC Open Software Platform Documentation
• embARC Open Software Platform Releases Page

Support

• Ask a question, report a bug or request an enhancement

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1. The memory map for EM SDP 1.2 firmware differs from the memory map for EM SDP 1.0 and 1.1. That is why there are different specs files. ↩