TMS320F28335, TMS320F28334, TMS320F28332
TMS320F28235, TMS320F28234, TMS320F28232
Digital Signal Controllers (DSCs)
www.ti.com
SPRS439C–JUNE 2007–REVISED FEBRUARY 2008
4.10 Serial Communications Interface (SCI) Modules (SCI-A, SCI-B, SCI-C)
The devices include three 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:
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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:
–
LSPCLK
(BRR ) 1) * 8
Baud rate =
when BRR ≠ 0
when BRR = 0
LSPCLK
16
Baud rate =
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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
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•
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•
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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)
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Separate enable bits for transmitter and receiver interrupts (except BRKDT)
150 MHz
Max bit rate +
+ 9.375 106 bńs
16
(for 150-MHz devices)
(for 100-MHz devices)
100 MHz
16
Max bit rate +
+ 6.25 106 bńs
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•
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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
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Peripherals
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