🕥 EM Starter Kit¶

Warning

EM Starter Kit board is no longer supported. There is no guarantee that this guide will be applicable for the latest tools.

Info

Please refer to board's documentation for detailed information about how to setup the board for initial operation.

Refer Getting OpenOCD and Using OpenOCD for details about installing and using OpenOCD.

Preface¶

EM Starter Kit board is shipped with with FPGA chip. There is a number of firmwares available for writing to it. Also, you can select one of the cores presented in the firmware. Here is a list of those firmwares and cores and corresponding target options for GCC:

Firmware	Core	GCC targets options
2.2, 2.3	EM11D	`-mcpu=em4_fpuda -mfpu=fpuda_all`
2.2, 2.3	EM9D	`-mcpu=em4_fpus -mfpu=fpus_all`
2.2, 2.3	EM7D	`-mcpu=em4_dmips`
2.1	EM7DFPU	`-mcpu=em4_fpuda -mmpy-option=wlh3`
2.1	EM7D	`-mcpu=em4_dmips -mmpy-option=wlh3`
2.1	EM5D	`-mcpu=em4_dmips -mmpy-option=wlh3`
2.0	EM7DFPU	`-mcpu=em4 -mswap -mnorm -mmpy-option=wlh3 -mbarrel-shifter -mfpu=fpuda_all`
2.0	EM7D	`-mcpu=em4 -mswap -mnorm -mmpy-option=wlh3 -mbarrel-shifter`
2.0	EM5D	`-mcpu=em4 -mswap -mnorm -mmpy-option=wlh3 -mbarrel-shifter`
1.0	EM6	`-mcpu=em4_dmips -mmpy-option=wlh5`
1.0	EM4	`-mcpu=em4_dmips -mmpy-option=wlh5`

In this guide we use EM7D core as an example. Also, the version of the EMSK firmware is considered to be 2.2 or 2.3.

Building an Application¶

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_dmips -specs=emsk2.2_em7d.specs main.c -o main.elf

-specs=emsk2.2_em7d.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	Firmware	Core	Description
`emsk2.2_em11d.specs`	2.2, 2.3	EM11D	Code and data are placed in ICCM and DCCM
`emsk2.2_em11d_ram.specs`	2.2, 2.3	EM11D	Code and data are placed in RAM
`emsk2.2_em9d.specs`	2.2, 2.3	EM9D	Code and data are placed in ICCM and DCCM
`emsk2.2_em9d_ram.specs`	2.2, 2.3	EM9D	Code and data are placed in RAM
`emsk2.2_em7d.specs`	2.2, 2.3	EM7D	Code and data are placed in ICCM and DCCM
`emsk2.2_em7d_ram.specs`	2.2, 2.3	EM7D	Code and data are placed in RAM
`emsk2.1_em7d.specs`	2.1	EM7D	Code and data are placed in ICCM and DCCM
`emsk2.1_em7d_ram.specs`	2.1	EM7D	Code and data are placed in RAM
`emsk2.1_em5d.specs`	2.1	EM5D	Code and data are placed in ICCM and DCCM
`emsk1_em6.specs`	1.0	EM6	Code and data are placed in ICCM and DCCM
`emsk1_em6_ram.specs`	1.0	EM6	Code and data are placed in RAM
`emsk1_em4.specs`	1.0	EM4	Code and data are placed in ICCM and DCCM

Running an Application Using OpenOCD¶

Follow Using OpenOCD guide and start OpenOCD with snps_em_sk_v2.2.cfg configuration file. Here is a possible output:

$ openocd -f board/snps_em_sk_v2.2.cfg
Open On-Chip Debugger 0.9.0-dev (2023-05-21-06:23)
Licensed under GNU GPL v2
For bug reports, read
    http://openocd.sourceforge.net/doc/doxygen/bugs.html
adapter speed: 5000 kHz
Info : clock speed 5000 kHz
Info : JTAG tap: arc-em.cpu tap/device found: 0x200044b1 (mfg: 0x258, part: 0x0004, ver: 0x2)
Info : JTAG tap: arc-em.cpu tap/device found: 0x200044b1 (mfg: 0x258, part: 0x0004, ver: 0x2)
target state: halted

Then connect to the server using GDB:

$ arc-elf32-gdb -quiet main.elf

# Connect. Replace 3333 with port of your choice if you changed it when starting OpenOCD
(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

Running an Application Using Ashling Opella-XD¶

Change directory to installation directory of Ashling Opella-XDand run the server (use your own path which is applicable for you machine):

$ cd <path-to-Ashling-directory>
$ ./ash-arc-gdb-server \
          --device arc-em \
          --arc-reg-file regs/opella-arcem-tdesc.xml \
          --jtag-frequency 5MHz
Ashling GDB Server for ARC (ash-arc-gdb-server).
v1.3.1, 29-Nov-2019, (c)Ashling Microsystems Ltd 2019.

Initializing connection ...
It is an ARC-v2 core!
IDENTITY:  00000042
MEMSUBSYS: 12047402
Connected to target device configured as: ARC-EM
(currently in Little Endian mode).
Connected to target via Opella-XD
(diskware: v1.4.3, 26-Jul-2019, firmware: v1.4.6-B, 05-Dec-2019) at 5MHz.
Waiting for debugger connection on port 2331 for core 1.
Press 'Q' to Quit.

Then connect to the server using GDB:

$ arc-elf32-gdb -quiet main.elf

# Connect to the GDB server
(gdb) target remote :2331

# Load a target description file
(gdb) set tdesc filename <path-to-Ashling-directory>/regs/opella-arcem-tdesc.xml

# 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

Connecting to the Serial Terminal¶

Follow the corresponding guide for ARC EM Starter Kit.