SM320F2808-EP Datasheet, PDF (62/118 Pages) Texas Instruments – Digital Signal Processors

SM320F2808-EP, SM320F2806-EP
SM320F2801-EP
Digital Signal Processors
SGLS316A – MARCH 2006 – REVISED FEBRUARY 2007
www.ti.com
4.8 Serial Communications Interface (SCI) Modules (SCI-A, SCI-B)
The 280x 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:
Baud rate =
LSPCLK
(BRR ) 1) * 8
when BRR ≠ 0
Baud rate =
LSPCLK
16
when BRR = 0
• 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
+
100 MHz
16
+
6.25
10⁶ bńs
• 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
The SCI port operation is configured and controlled by the registers listed in Table 4-8 and Table 4-9.
62
Peripherals
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