.. _usart: USART ===== A USART is more commonly known a *serial port*. It's used to transmit information between Maple and another device (like your computer, another Maple, etc.). .. contents:: Contents :local: Hardware/Circuit Design ----------------------- .. TODO [0.0.12] Add some more information here (like how you should .. connect TX_a to RX_b and RX_a to TX_b). .. TODO [0.0.12/Maple Native] UART4 and UART5, Native links Each LeafLabs board has at least 3 separate USART devices. In the most simple use case, the RX and TX pins are used to send data at a predetermined speed (or *baud rate*). Their usage is documented in the :ref:`Serial Ports <lang-serial>` language reference page. Which pins correspond to the USART TX and RX pins are given on your board's silkscreen, and also in the board-specific USART pin maps available here: * :ref:`Maple <maple-usart-map>` * :ref:`Maple RET6 Edition <maple-ret6-usart-map>` * :ref:`Maple Mini <maple-mini-usart-map>` If you use a particular serial port, you cannot also use its communication pins for other purposes at the same time. Compatible Devices and Specifications ------------------------------------- We have successfully used the USART ports with an FT232R-based USB-serial converter at up to 115200 baud. Higher speeds should certainly be possible. Recommended Reading ------------------- * `Wikipedia article on Universal Asynchronous Receiver/Transmitter (USART) <http://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitter>`_ * `Arduino Serial reference <http://arduino.cc/en/Reference/Serial>`_ * ST `Reference Manual RM0008 <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (PDF), Chapter 27.