SoC Simulator is a simple SoC (System-on-chip) + Board emulator intended to practice programming in FreeRTOS for a MCU.
It uses freertos-addons to allow using FreeRTOS on a Linux box. Edit Makefile to point variables to installation directory. It uses imgui to build a GUI to show input/output and devices virtually connected to the MCU. Current set-up uses SDL and OpenGL implementation.
The emulator includes a HAL (HAL.h) to interface with the emulated Hardware.
The Hardware is emulated in the following files:
This project is licensed by GPLv3. See LICENSE file for more details.
It is required a C/C++ compiler compatible with C++17. Tested with gcc 10.2.0 on ubuntu.
git clone https://github.com/FreeRTOS/FreeRTOS-Kernel.git
git clone https://github.com/michaelbecker/freertos-addons.git
git clone https://github.com/mariusmm/SoCSIM.git
cd SoCSIM
SDL2 is required, install it with:
sudo apt install libsdl2-dev libsdl2-2.0-0
Build is based on cmake, so in SoCSIM directory run the following commands:
mkdir build
cd build
cmake ..
make
./SoCSIM
cd build
make doc
The documentation is generated in doc/ directory in html and latex format.
In case you want to generate pdf from latex, you need to run make in the doc/latex/ directory
There are 4 GPIO ports (PORTA, PORTB, PORTC & PORTD).
- Button 1 is connected to PORTA, pin #0
- Button 2 is connected to PORTB, pin #1
- LED 1 is connected to PORTC, pin #7
- LED 2 is connected to PORTD, pin #12
There is a basic Interrupt Controller with only two registers, NVIC_CTRL and NVIC_IRQ.
This timer is only able to generate a PWM signal, it counts from 0 to value ADDR_TIMER_TOP and starts over. When timer value is less than ADDR_TIMER_CMP output is '0', when greater output is '1'.
Timer input clock runs at 16 MHz and can be pre-scaled by a value from 1 to 256 (powers of 2 only).
A very basic RTC timer, with 1 second precision that store seconds in the RTC_CNT register (32 bits). It also has a compare register (RTC_CMP) to trigger an IRQ if both registers are equal.
An ITM-like peripheral with a single register that prints out the characters written to its data register.
DAC peripheral able to generate a signal between 0 and 1 volts. The DAC works a 10 samples/second in continuous mode.
- DAC_CTRL bit0 enables (1) /disables (0) DAC peripheral.
- DAC_TRL bit7 enables (1) / disables (0) DAC IRQ. DAC triggers a IRQ when conversion is complete.
- DAC_DATA bit 11-0 Data register (12 bits)
Watchdog peripheral that can halt de simulation (simulating a system reset). It includes a prescaler. The watchdog has a clock of 128 kHz and the counter starts with 2048. When counter reaches 0 resets the system (halts de simulation). There is a prescaler (WDOG_CTRL bits 15 to 8) to the input clock (powers of 2). Once enabled (WDOG_CTRL bit 0 to '1') watchdog can't be disabled.
To properly feed the Watchdog, the magic number 0x00505345 must be written to register WDOG_CMD.
All registers are 32 bit width.
| Address | Register | Comment |
|---|---|---|
| 0x1000 | GPIO A CTRL | 1 - out , 0 - in |
| 0x1004 | GPIO A INT | 1 - Interrupt enable, 0 - Disabled |
| 0x1008 | GPIO A OUT | '1' or '0' set to output pin |
| 0x100C | GPIO A IN | '1' or '0' set by the input pin |
| 0x2000 | GPIO B CTRL | idem |
| 0x2004 | GPIO B INT | idem |
| 0x2008 | GPIO B OUT | idem |
| 0x200C | GPIO B IN | idem |
| 0x3000 | GPIO C CTRL | idem |
| 0x3004 | GPIO C INT | idem |
| 0x3008 | GPIO C OUT | idem |
| 0x300C | GPIO C IN | idem |
| 0x4000 | GPIO D CTRL | idem |
| 0x4004 | GPIO D INT | idem |
| 0x4008 | GPIO D OUT | idem |
| 0x400C | GPIO D IN | idem |
| 0xA000 | INTERRUPT CTRL | TBD |
| 0xA004 | INTERRUPT IRQ | TBD |
| 0xC000 | ADDR TIMER CTRL | Prescaler (15:8), |
| 0xC000 | ADDR TIMER TOP | Top value |
| 0xC000 | ADDR TIMER CNT | Timer counter value |
| 0xC000 | ADDR TIMER CMP | Compare value |
| 0xD000 | ADDR RTC CTRL | RTC control register |
| 0xD004 | ADDR RTC CNT | RTC epoch time |
| 0xD008 | ADDR RTC CMP | RTC compare register |
| 0xF000 | ADDR TRACE | ITM like tracer |
| 0x10000 | ADDR DAC CTRL | DAC control register |
| 0x10004 | ADDR DAC DATA | DAC sample register |
| 0x80000 | ADDR_WDOG_CTRL | Watchdog Ctrl register |
| 0x80004 | ADDR_WDOG_CMD | Watchdog command register |