... , 20KB SRAM, 2 × SPI, 2 × I2C, USB, CAN, PWM, 2 × ADC, 3 × USART, 3 16-bit timer - 8 / 16 bit microcontroller ... • 1 adjustable analog voltage control input for the ADC is used to test the ADC STM32F103 characteristics. • 1 speakers used to test ... the PWM timer function to drive speakers, by changing the ADC potentiometer, given different frequencies of sound. I2C test: reading and ...