Software UART implementation allows developers to establish serial communication on microcontrollers lacking available hardware UART pins. The method utilizes DMA, hardware timers, and GPIO to manage data transmission and reception.
For data transmission, the system uses a binary DAC approach. A bitstream is generated and placed into a binary queue, which is then processed via DMA. To maintain signal integrity, the transmission size must be a multiple of the frame size.
Data reception involves a two-stage process: capturing samples using cyclic DMA and processing them through a finite state machine. The system operates in real-time, requiring efficient handling of sample arrays to prevent data loss.
The implementation requires significant resources, including RAM for queues, CPU time for signal processing, two DMA streams, and one or two hardware timers. The author tested the solution on an STM32F407ZGT6 microcontroller.
