Datasheet

rateBaud
8*1)(BRR
LSPCLK
+
=
0BRRwhen ¹
16
LSPCLK
=
0BRRwhen =
TMS320F2810, TMS320F2811, TMS320F2812
TMS320C2810, TMS320C2811, TMS320C2812
www.ti.com SPRS174T –APRIL 2001–REVISED MAY 2012
4.6 Serial Communications Interface (SCI) Module
The F281x and C281x devices include two serial communications interface (SCI) modules. The SCI
modules support digital communications between the CPU and other asynchronous peripherals that use
the standard non-return-to-zero (NRZ) format. The SCI receiver and transmitter are double-buffered, and
each has its own separate enable and interrupt bits. Both can be operated independently or
simultaneously in the full-duplex mode. To ensure data integrity, the SCI checks received data for break
detection, parity, overrun, and framing errors. The bit rate is programmable to over 65000 different speeds
through a 16-bit baud-select register.
Features of each SCI module include:
• Two external pins:
– SCITXD: SCI transmit-output pin
– SCIRXD: SCI receive-input pin
NOTE: Both pins can be used as GPIO if not used for SCI.
• Baud rate programmable to 64K different rates
(3)
• Data-word format
– One start bit
– Data-word length programmable from one to eight bits
– Optional even/odd/no parity bit
– One or two stop bits
• Four error-detection flags: parity, overrun, framing, and break detection
• Two wake-up multiprocessor modes: idle-line and address bit
• Half- or full-duplex operation
• Double-buffered receive and transmit functions
• Transmitter and receiver operations can be accomplished through interrupt-driven or polled algorithms
with status flags.
– Transmitter: TXRDY flag (transmitter-buffer register is ready to receive another character) and TX
EMPTY flag (transmitter-shift register is empty)
– Receiver: RXRDY flag (receiver-buffer register is ready to receive another character), BRKDT flag
(break condition occurred), and RX ERROR flag (monitoring four interrupt conditions)
• Separate enable bits for transmitter and receiver interrupts (except BRKDT)
• Max bit rate = 75 MHz/16 = 4.688 x 10
6
b/s
• NRZ (non-return-to-zero) format
• Ten SCI module control registers located in the control register frame beginning at address 7050h
NOTE: All registers in this module are 8-bit registers that are connected to Peripheral Frame 2. When
a register is accessed, the register data is in the lower byte (7–0), and the upper byte (15–8) is read as
zeros. Writing to the upper byte has no effect.
Enhanced features:
• Auto baud-detect hardware logic
• 16-level transmit/receive FIFO
(3) Serial port performance is limited by I/O buffer switching speed. Internal prescalers must be adjusted such that the peripheral speed is
less than the I/O buffer speed limit—20 MHz maximum.
Copyright © 2001–2012, Texas Instruments Incorporated Peripherals 77
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