SC16C754B NXP Semiconductors, SC16C754B Datasheet - Page 10

• Manufacturer Part Number: SC16C754B
• Description: 5 V - 3.3 V and 2.5 V quad UART - 5 Mbit/s (max.)
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SC16C754B_4
Product data sheet
Fig 5.
D7 to D0
Autoflow control (auto-RTS and auto-CTS) example
6.2 Hardware flow control
Hardware flow control is comprised of auto-CTS and auto-RTS. Auto-CTS and auto-RTS
can be enabled/disabled independently by programming EFR[7:6].
With auto-CTS, CTS must be active before the UART can transmit data.
Auto-RTS only activates the RTS output when there is enough room in the FIFO to receive
data and de-activates the RTS output when the RX FIFO is sufficiently full. The halt and
resume trigger levels in the TCR determine the levels at which RTS is
activated/deactivated.
If both auto-CTS and auto-RTS are enabled, when RTS is connected to CTS, data
transmission does not occur unless the receiver FIFO has empty space. Thus, overrun
errors are eliminated during hardware flow control. If not enabled, overrun errors occur if
the transmit data rate exceeds the receive FIFO servicing latency.
FIFO
FIFO
TX
RX
UART 1
SERIAL TO
TO SERIAL
PARALLEL
PARALLEL
CONTROL
CONTROL
FLOW
FLOW
5 V, 3.3 V and 2.5 V quad UART, 5 Mbit/s (max.) with 64-byte FIFOs
Rev. 04 — 6 October 2008
RTS
CTS
RX
TX
TX
CTS
RX
RTS
SERIAL TO
TO SERIAL
PARALLEL
PARALLEL
CONTROL
CONTROL
FLOW
FLOW
UART 2
FIFO
FIFO
SC16C754B
RX
TX
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