User's Manual

© SENSITECH INC. CONFIDENTIAL – CONTROLLED DOCUMENT Page 35 of 83
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PART NUMBER T82002163
REV A
FIFO buffers data from the serial link until it is read by the processor. In non-FIFO mode, the
transmit and receive FIFOs are bypassed.
Each UART includes a programmable baud-rate generator that can divide the input clock by 1 to
(216 – 1). This produces a 16X clock that can be used to drive the internal transmit and receive
logic. Software can program interrupts to meet its requirements, which minimizes the number of
computations required to handle the communications link. Each UART operates in an environment
that is either controlled by software and can be polled or is interrupt-driven.
All three UARTs support the 16550A and 167502 functions, but are slightly different in the features
supported.
Full-Function UART
The FFUART supports modem-control capability. The maximum baud rate is 921,600 bps.
Bluetooth UART
The BTUART is a high-speed UART that supports baud rates up to 921,600 bps and can be
connected to a Bluetooth module. It supports the functions in the feature list, but supports only two
modem control pins (nCTS and nRTS).
1. Infrared Data Association, Serial Infrared Physical Layer Link Specification, October 17, 1995, Version
1.1
2. The 16550A was originally produced by National Semiconductor Inc. The 16750 is produced as the
TL16C750 by Texas Instruments.
The STUART supports all functions in the feature list, but does not support modem-control
capability. The maximum baud rate is 921,600 bps.
Compatibility with 16550A and 16750
The UARTs are functionally compatible with the 16550A and 16750 industry standards. Each
UART supports most of the 16550A and 16750 functions, as well as the following features:
• 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 threshold
• Auto baud-rate detection
• Auto flow
Features
The UARTs share the following features:
• Functionally compatible with the 16550A and 16750
• Ability to add or delete standard asynchronous communication 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, nDSR, nDTR, nRI, and nDCD)
• Auto-flow capability controls data I/O without generating interrupts:
— nRTS (output) controlled by UART receive 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