CS452 - Real-Time Programming - Spring 2009

Lecture 16 - Serial Hardware

Practical Details

Interrupt Handling

  1. How are you handling hardware interrupts?

Serial Hardware

See pdf.

FIFO

Why do FIFOs exist in UARTS?

Interrupts

Five interrupts in the device

  1. Transmit
  2. Receive
  3. Modem status
  4. Receive timeout
  5. Combined

Three inputs to the PIC

  1. Transmit
  2. Receive
  3. Combined

Easy way to use interrupts

Enable only combined; read UART registers to decide what to do.

Think of the receive and transmit parts of the UART as separate state machines

Handy Features

Loopback


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