SC16C752BIBS Philips Semiconductors, SC16C752BIBS Datasheet - Page 11

• Manufacturer Part Number: SC16C752BIBS
• Description: 5 V/ 3.3 V and 2.5 V dual UART/ 5 Mbit/s (max.)/ with 64-byte FIFOs
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 14443
Product data
6.3.3 Software flow control example
Assumptions:
using software flow control with single character Xoff (0F) and Xon (0D) tokens. Both
have Xoff threshold (TCR[3:0] = F) set to 60, and Xon threshold (TCR[7:4] = 8) set to
32. Both have the interrupt receive threshold (TLR[7:4] = D) set to 52.
UART 1 begins transmission and sends 52 characters, at which point UART2 will
generate an interrupt to its processor to service the RCV FIFO, but assume the
interrupt latency is fairly long. UART1 will continue sending characters until a total of
60 characters have been sent. At this time, UART2 will transmit a 0F to UART1,
informing UART1 to halt transmission. UART1 will likely send the 61
UART2 is sending the Xoff character. Now UART2 is serviced and the processor
reads enough data out of the RX FIFO that the level drops to 32. UART2 will now
send a 0D to UART1, informing UART1 to resume transmission.
Fig 7. Software flow control example.
SERIAL-TO-PARALLEL
PARALLEL-TO-SERIAL
TRANSMIT FIFO
5 V, 3.3 V and 2.5 V dual UART, 5 Mbit/s (max.), with 64-byte FIFOs
Xon-1 WORD
Xon-2 WORD
Xoff-1 WORD
Xoff-2 WORD
UART1 is transmitting a large text file to UART2. Both UARTs are
Rev. 03 — 14 December 2004
UART1
Xoff–Xon–Xoff
programmed
characters
compare
Xon-Xoff
data
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
SERIAL-TO-PARALLEL
PARALLEL-TO-SERIAL
RECEIVE FIFO
Xon-2 WORD
Xon-1 WORD
Xoff-1 WORD
Xoff-2 WORD
SC16C752B
UART2
st
character while
002aaa229
11 of 47