SMJ320F240 Datasheet, PDF (45/99 Pages) Texas Instruments – DSP CONTROLLER

SMJ320F240
DSP CONTROLLER
SGUS029 – APRIL 1999
serial communications interface (SCI) module
The SMJ320F240 devices include a serial communications interface (SCI) module. The SCI module supports
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 (baud) is programmable to over 65 000 different speeds through a 16-bit baud-select register.
Features of the SCI module include:
D Two external pins
– SCITXD: SCI transmit-output pin or general-purpose bidirectional I/O pin
– SCIRXD: SCI receive-input pin or general-purpose bidirectional I/O pin
D Baud rate programmable to 64K different rates
– Up to 625 Kbps at 10-MHz SYSCLK
D 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
D Four error-detection flags: parity, overrun, framing, and break detection
D Two wake-up multiprocessor modes: idle-line and address bit
D Half- or full-duplex operation
D Double-buffered receive and transmit functions
D 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 (monitoring four interrupt conditions)
D Separate enable bits for transmitter and receiver interrupts (except BRKDT)
D NRZ (non return-to-zero) format
D Eleven 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 interfaced to the 16-bit peripheral bus. 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.
Figure 14 shows the SCI module block diagram.
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