17-2 Intel® PXA26x Processor Family Developer’s Manual
Hardware UART
17.2 Features
The HWUART has the following features:
Functionally compatible with the 16550A and 16750 UART specifications. The UART
supports not only the 16550A and 16750 industry standards but these additional functions as
well:
DMA requests for transmit and receive data services
Slow infrared asynchronous interface
Non-Return-to-Zero (NRZ) encoding/decoding function
64 byte transmit/receive FIFO buffers
Programmable receive FIFO trigger thre shold
Auto baud-rate detection
Auto flow
Ability to add or delete standard asynchronous communications bits (start, stop, and parity) in
the serial data
Independently controlled transmit, receive, line status, and data set interrupts
Programmable baud rate generator that allows the internal clock to be divided by 1 to 216–1 to
generate an internal 16X clock
Modem control functions (nCTS, nRTS)
Autoflow capability controls data I/O without generating Interrupts:
nRTS (output) controlled by UAR T Receiver FIFO
nCTS (input) from modem controls UART transmitter
Fully programmable serial-interface:
5-, 6-, 7-, or 8-bit characters
Even, odd, and no parity detection
1, 1.5, or 2 stop bit generation
Baud rate generation up to 921.6Kbps
False start bit detection.
64-byte transmit FIFO
64-byte receive FIFO
Complete status reporting capability
Ability to generate and detect line breaks
Internal diagnostic capabilities that include:
Loopback controls for communications link fault isolation
Break, parity, and framing error sim ulation
Fully prioritized interrupt system controls
Separate DMA requests for transmit and receive data services