[Tinyos-devel] Proposed UART Changes

[Philip Levis]

Here's a first cut at a UartControl interface. I've also attached a  
full source file. Hopefully the comments give a sense of the  
semantics. Note that this interface causes state changes in other  
(receive/transmit) interfaces. We generally try to avoid this when  
possible, but there are times when the benefits outweigh the costs.  
I.e. tying them together would require unifying event handlers and  
configuration.

2 major changes: async operations and comments.

Comments/feedback welcome.

interface UartControl {

   /**
    * Enables the UART receive path, such that
    * the system will issue interrupts when it
    * receives data.
    */
   async command error_t enableRx();

   /**
    * Disables the UART receive path. After
    * this call returns, there will be no further
    * receive interrupts until enableRx is called.
    */
   async command error_t disableRx();

   /**
    * Returns whether UART reception is enabled.
    *
    */
   async command bool rxEnabled();


   /**
    * Enables the UART transmit path, such that
    * the system is able to send bytes.
    */
   async command error_t enableTx();

   /**
    * Disables the UART transmit path. After
    * this command returns, attempts to send
    * bytes will return EOFF.
    */
   async command error_t disableTx();

   /**
    * Returns whether UART transmission is
    * enabled.
    */
   async command bool txEnabled();

   // TOS_UART_2400, TOS_UART_57600, etc.

   /**
    * Set the UART speed for both reception
    * and transmission. This command should only
    * be called when both reception and transmission
    * are disabled. The speed should be an constant
    * of the form TOS_UART_XX, where XX is the speed,
    * such as TOS_UART_57600. Different platforms
    * support different speeds.
    */

   async command error_t setSpeed(uart_speed_t spd);

   /**
    * Return the current UART speed.
    */
   async command uart_speed_t speed();

   /**
    * Set whether UART bytes have even parity bits,
    * odd parity bits, or no parity bits. This command
    * should only be called with both the receive
    * and transmit paths are disabled.
    */
   // TOS_PARITY_NONE, TOS_PARITY_EVEN, TOS_PARITY_ODD, etc.
   async command error_t setParity(uart_parity_t par);

   /**
    * Return the current parity setting.
    */
   async command uart_parity_t parity();

   /**
    * Enable stop bits. This command should only be called
    * when both the receive and transmit paths are disabled.
    */
   async command error_t setStop();

   /**
    * Disable stop bits. This command should only be called
    * when both the receive and transmit paths are disabled.
    */
   async command error_t setNoStop();

   /**
    * Returns whether stop bits are enabled.
    */
   async command bool stopBits();
}



Phil

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