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6. Embedded programing

Assignments in this week

Group Assignment:
- [x] browse through the data sheet for your microcontroller
- [x] compare the performance and development workflows for other architectures

Individual assignment:
- [x] write a program for a microcontroller development board that you made
- [x] to interact (with local input &/or output devices)
- [x] and communicate (with remote wired or wireless devices)
- [x] extra credit: use different languages &/or development
- [x] extra credit: connect external components to the board

Datasheet of different microcontrollers

Comparison with diffrent microcontrollers.

RP2040 vs STM32 vs SAMD21 vs ESP32-S3

RP2040 vs STM32 vs SAMD21 vs ESP32-S3

Raspberry Pi RP2040 STM32F103C8T6 ATSAMD21G18 ESP32-S3
Product Image
Dev Board Raspberry Pi Pico Blue Pill MKRZero, Seeed XIAO ESP-S3, Seeed XIAO
Cores Dual-Core Single Core Single Core Dual-Core
Core Architechture 32-bit ARM Coretex-M0+ 32-bit ARM Coretex-M3 32-bit ARM Coretex-M0+ Xtensa® 32-bit LX7
Flexible Clock up to 133MHZ 72MHz 48MHz Up to 240 MHz
RAM Size 264 KByte SRAM 20 KByte 32 KByte 512 KByte SRAM
Flash Size Up to 16 MByte external Flash 64 KByte 256 KByte Up to 1 GByte external Flash
DIrect Memory Access 12 x DMA 7 x DMA 12 x DMA 3 x DMA
Wireless None None None IEEE 802.11b/g/n
Programming Lanuage MicroPython, CircuitPython, C/C++, Arduino C alike, Arduino IDE C alike, Arduino IDE Espressif IDF, Arduino IDE, CircuitPython
MCU Power Voltage 3.3VDC 3.3VDC 3.3VDC 3.3VDC
USB Interface USB 1.1 Device and Host USB 2.0 Full Speed USB OTG USB OTG
Program Laoding USB Mass Storage, UF2 External device, Serial USB, UF2 USB, UF2
GPIO 30 x Digital Input/Output 37 x GPIO 38 x GPIO 45 x GPIO
High-Speed PIO 2 blocks, 8 x State Machine, 8 × 10 No No No
ADC 4 x 12-bit 10 x 12-bit 12 x 12-bit 2 × 12-bit SAR ADCs, up to 20 channels
DAC No No 1 x 10-bit 2 x 8-bit
UART 2 3 6 x Sercom (UART, I2C, SPI) 3
I2C 2 2 6 x Sercom (UART, I2C, SPI) 2
SPI 2 3 6 x Sercom (UART, I2C, SPI) 4
PWM 16 15 20 2 × MCPWM
On Chip Sensor Temperature No No Temperature
IC Package QEN-56 LQFP-48 48-pin TQFP, QFN, WLCSP VFQFN-56
Retail Price USD 1.00 USD 3.50 USD 3.15 USD 1.20

Reference

In this week’s course, I learned various knowledge about embedded programming. As a former embedded engineer, we will all retain the habit of studying datasheets. Based on the classification of microcontrollers that are currently on the market, I selected several important specifications to study and read, such as RP2040,STM32,ATSAMD12,ESP32-S3.
In terms of length, RP2040 is currently the most detailed datasheet.According to the latest information, 640 pages of information detail the origin, parameters and usage specifications of the chip. As a former embedded engineer, we often pay more attention to the performance processing parameters of the chip and some interface design references, so that developers and engineers can design chip reference development boards according to their own needs.

Programing on XIAO ESPS3

1. Install Arduino IDE and board manager

Installing the Arduino Ide is a relatively painless task. But when I installed the board manager according to Seeed XIAO’s WIKI, an error occurred. The main reason for the error was due to the timeout of loading the github library resources. After continuous inquiries, I found the reason. Due to VPN problems, I was unable to obtain the library files in real time, which resulted in the loading failure.

After successfully installing the library files, you can finally select the board model in the Arduino IDE. I used the Blink program in the sample program. By compiling and uploading the program, I can finally see that the right LED of XIAO ESP32 flashes.

3. Microphone Testing for XIAO ESP32 Sense

According to XIAO’s product introduction, the board integrates peripherals such as a microphone, so I will follow the tutorial to test the microphone peripherals and train through edge pulse.
- A. Initialize the Micro SD card: Since XIAO ESP32 requires a memory card in FAT32 format, I first found a memory card to initialize it to facilitate subsequent storage of sound files collected by the microphone.
- B. Test the microphone function and monitor the sound through the serial port: After compiling and uploading the program, we can set the corresponding baud rate through the serial port for signal observation. After shouting to XIAO loudly, we can clearly see the signal displayed on the serial port. The value increases and changes occur.

Sample Code for XIAO ESP32S3 Microphone Testing #include <I2S.h> void setup() { // Open serial communications and wait for port to open: // A baud rate of 115200 is used instead of 9600 for a faster data rate // on non-native USB ports Serial.begin(115200); while (!Serial) { ; // wait for serial port to connect. Needed for native USB port only }
// start I2S at 16 kHz with 16-bits per sample I2S.setAllPins(-1, 42, 41, -1, -1); if (!I2S.begin(PDM_MONO_MODE, 16000, 16)) { Serial.println(“Failed to initialize I2S!”); while (1); // do nothing } }

    void loop() {
      // read a sample
      int sample = I2S.read();     
      if (sample && sample != -1 && sample != 1) {
        Serial.println(sample);
      }
    } `

4. XIAO ESP32S3 Sense Keywords Spotting via TinyML EdgeImpules

  • A.Capturing the offline audio data:
    As we all know, if you need to train an AI model, the first step you need to do is to obtain the original data set to facilitate subsequent model training. According to the tutorial, we collected 2 sets of data respectively with the keywords “hello” and “crail” through XIAO ESP32S3. Each set of data is about 10 seconds in length, and finally saved in the microSD card. Since I am currently just testing, there are not many data samples collected. If you want to conduct more accurate AI model training, more data sets will be more helpful for model generation.
  • B.Uploading collected sound data to Edgeimpluse then make pre-processing and model defining: