SC16C550IN40 NXP Semiconductors, SC16C550IN40 Datasheet - Page 13

• Manufacturer Part Number: SC16C550IN40
• Manufacturer: NXP Semiconductors

Specifications of SC16C550IN40

• Transmit Fifo: 16Byte
• Receive Fifo: 16Byte
• Transmitter And Receiver Fifo Counter: Yes
• Package Type: PDIP
• Operating Supply Voltage (max): 5.5V
• Mounting: Through Hole
• Pin Count: 40
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Number Of Channels: 1
• Lead Free Status / RoHS Status: Compliant

Philips Semiconductors
9397 750 11619
Product data
Fig 8. RTS functional timing waveforms, RCV FIFO trigger level = 14 bytes.
(1) RTS is de-asserted when the receiver receives the first data bit of the sixteenth byte. The receive FIFO is full after finishing
(2) RTS is asserted again when there is at least one byte of space available and no incoming byte is in processing, or there is
(3) When the receive FIFO is full, the first receive buffer register read re-asserts RTS.
(RD RBR)
the sixteenth byte.
more than one byte of space available.
RTS
IOR
RX
6.4 Software flow control
BYTE 14
When software flow control is enabled, the SC16C550 compares one or two
sequential receive data characters with the programmed Xon or Xoff character
value(s). If receive character(s) (RX) match the programmed values, the SC16C550
will halt transmission (TX) as soon as the current character(s) has completed
transmission. When a match occurs, the receive ready (if enabled via Xoff IER[5])
flags will be set and the interrupt output pin (if receive interrupt is enabled) will be
activated. Following a suspension due to a match of the Xoff characters’ values, the
SC16C550 will monitor the receive data stream for a match to the Xon1,2 character
value(s). If a match is found, the SC16C550 will resume operation and clear the flags
(ISR[4]).
Reset initially sets the contents of the Xon/Xoff 8-bit flow control registers to a logic 0.
Following reset, the user can write any Xon/Xoff value desired for software flow
control. Different conditions can be set to detect Xon/Xoff characters and
suspend/resume transmissions. When double 8-bit Xon/Xoff characters are selected,
the SC16C550 compares two consecutive receive characters with two software flow
control 8-bit values (Xon1, Xon2, Xoff1, Xoff2) and controls TX transmissions
accordingly. Under the above described flow control mechanisms, flow control
characters are not placed (stacked) in the user accessible RX data buffer or FIFO.
When using a software flow control the Xon/Xoff characters cannot be used for data
transfer.
In the event that the receive buffer is overfilling and flow control needs to be executed,
the SC16C550 automatically sends an Xoff message (when enabled) via the serial
TX output to the remote modem. The SC16C550 sends the Xoff1,2 characters as
soon as received data passes the programmed trigger level. To clear this condition,
the SC16C550 will transmit the programmed Xon1,2 characters as soon as receive
data drops below the programmed trigger level.
RTS RELEASED AFTER THE
FIRST DATA BIT OF BYTE 16
BYTE 15
Rev. 05 — 19 June 2003
START
BYTE 16
UART with 16-byte FIFO and IrDA encoder/decoder
STOP
© Koninklijke Philips Electronics N.V. 2003. All rights reserved.
START
BYTE 18
SC16C550
STOP
002aaa051
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