Learn with SHAKTI

Using Arty-7 100T with SHAKTI

STEP 1: Prerequisites

Note: Please ensure SHAKTI C Class is programmed onto the Arty-7 100t board

1. Install the required packages.

sudo apt-get install python-serial

If you face any error while running any command, Please refer FAQ section.

2. Please ensure SHAKTI toolchain is installed successfully.

which riscv64-unknown-elf-gcc

/path-to-shakti-tools/riscv64/bin/riscv64-unknown-elf-gcc

which openocd

/path-to-shakti-tools/bin/openocd

3. Please connect Arty-7 100t board to the system using the microUSB cable.

Step 2: Write a simple C program to print Hello world

Copy paste the below content in it and save it as first.c

#include "uart.h"

int main()
{
printf("hello, world");
return (0);
}

STEP 3: Compile and Build

1. Move inside the spiking folder and update it.

cd spiking
git pull

2. In the spiking folder, Run the below commands to compile first.c for SHAKTI. The necessary header and linker files are included in the spiking repository.

To generate crt.o from crt.S which is available in spiking folder.

riscv64-unknown-elf-gcc -mcmodel=medany -static -std=gnu99 -fno-builtin-printf -c crt.S -o crt.o

To generate syscalls.shakti from syscalls.c which is available in spiking folder.

riscv64-unknown-elf-gcc -mcmodel=medany -static -std=gnu99 -fno-builtin-printf -c syscalls.c -o syscalls.shakti -lm -lgcc

To generate uart.o from uart.c which is available in spiking folder.

riscv64-unknown-elf-gcc -mcmodel=medany -static -std=gnu99 -fno-builtin-printf -c uart.c -o uart.o -lm -lgcc

To generate first.o from first.c which is the file created in the earlier step.

riscv64-unknown-elf-gcc -mcmodel=medany -static -std=gnu99 -fno-builtin-printf -c first.c -o first.o -lm -lgcc

To link all the object files (.o, .shakti) using the linker file link.ld.

riscv64-unknown-elf-gcc -T link.ld first.o uart.o crt.o syscalls.shakti -o first.shakti -static -nostartfiles -lm -lgcc

STEP 4: Debugging

The Arty-7 100T board is programmed with SHAKTI C class SoC. Please ensure Arty-7 100T board is connected to the the Host PC.

The Arty-7 100T board should be attached to the OpenOCD debugger, in order to debug your program using the RISC-V GNU Debugger (GDB) software. Read how RISC-V GDB and OpenOCD work together to establish a connection between the Microprocessor and Host PC.
Since we have built the application, already. We can straight away load it to the Arty-7 100T board and test.

The following steps list out the actions to be taken,

If you face any error while running any command, Please refer FAQ section.

TERMINAL 1: Open a serial port in this terminal, Here the output of the program is displayed.

sudo miniterm.py /dev/ttyUSB0 19200

--- Miniterm on /dev/ttyUSB0  19200,8,N,1 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---

Note: "/dev/ttyUSB0" - ttyUSB means "USB serial port adapter" and the "0" ( "0" or "1" or "2") is the USB device number to which the board is connected and 19200 is the default baud rate.

TERMINAL 2: Open a new terminal and move to spiking folder. Here, run OpenOCD with the ftdi.cfg.

sudo $(which openocd) -f ftdi.cfg
[sudo] password for rise:

Open On-Chip Debugger 0.10.0+dev-00615-gfd9c54b (2019-07-12-15:10)
Licensed under GNU GPL v2
For bug reports, read
http://openocd.org/doc/doxygen/bugs.html
adapter speed: 1000 kHz
none separate
Info : auto-selecting first available session transport "jtag". To
override use 'transport select '.
Info : Simple Register based Bscan Tunnel Selected
Info : clock speed 1000 kHz
Info : JTAG tap: riscv.cpu tap/device found: 0x13631093 (mfg: 0x049
(Xilinx), part: 0x3631, ver: 0x1)
Info : datacount=12 progbufsize=0
Warn : We won't be able to execute fence instructions on this target.
Memory may not always appear consistent. (progbufsize=0, impebreak=0)
Info : Examined RISC-V core; found 1 harts
Info :  hart 0: XLEN=64, misa=0x800000000014112d
Info : Listening on port 3333 for gdb connections
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : accepting 'gdb' connection on tcp/3333

TERMINAL 3: Open a new terminal and move to spiking folder. Now start the gdb debugging session by running below command. What are the most used RISC-V GDB Commands?

riscv64-unknown-elf-gdb

GNU gdb (GDB) 9.1
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later < http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "--host=x86_64-pc-linux-gnu --target=riscv64-unknown-elf".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
< http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    < http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word".

(gdb) set remotetimeout unlimited

(gdb) target remote localhost:3333

Remote debugging using localhost:3333
warning: No executable has been specified and target does not support
determining executable automatically.  Try using the "file" command.
Python Exception  'gdb.Inferior'
object has no attribute 'progspace':
0x0000000000000004 in ?? ()

(gdb) file first.shakti

A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading symbols from first.shakti...(no debugging symbols found)...done.

(gdb) load

Loading section .text.init, size 0x1c2 lma 0x80000000
Loading section .tohost, size 0x48 lma 0x80001000
Loading section .text, size 0x1018 lma 0x80001048
Loading section .rodata, size 0x1b0 lma 0x80002060
Start address 0x80000000, load size 5074
Transfer rate: 6 KB/sec, 1268 bytes/write.

(gdb)  c

Continuing.

Switch to TERMINAL 1 to view the output of the C program.

sudo miniterm.py /dev/ttyUSB0 19200

--- Miniterm on /dev/ttyUSB0  19200,8,N,1 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---

hello, world