sc16c850iet NXP Semiconductors, sc16c850iet Datasheet - Page 35

• Manufacturer Part Number: sc16c850iet
• Description: Sc16c850 2.5 V To 3.3 V Uart, 5 Mbit/s Max. With 128-byte Fifos, Infrared Irda , And 16 Mode Or 68 Mode Parallel Bus Interface
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SC16C850_1
Product data sheet
7.20 RS-485 Turn-around time delay (RS485TIME)
7.21 Advanced Feature Control Register 2 (AFCR2)
The value in this register controls the turn-around time of the external line transceiver in
bit time. In automatic 9-bit mode RTS or DTR pin is used to control the direction of the line
driver, after the last bit of data has been shifted out of the transmit shift register the UART
will count down the value in this register. When the count value reaches zero, the UART
will assert RTS or DTR pin (logic 0) to turn the external RS-485 transceiver around for
receiving.
Table 30.
Table 31.
Bit
7:0
Bit
7:6
5
4
3
2
1
0
Symbol
RS485TIME[7:0]
Symbol
AFCR2[7:6]
AFCR2[5]
AFCR2[4]
AFCR2[3]
AFCR2[2]
AFCR2[1]
AFCR2[0]
RS-485 programmable turn-around time register bits description
Advanced Feature Control Register 2 register bits description
2.5 V to 3.3 V UART with 128-byte FIFOs and IrDA encoder/decoder
Rev. 01 — 10 January 2008
Description
reserved
RTSInvert. Invert RTS or DTR signal in automatic 9-bit mode.
RTSCon. Enable the transmitter to control RTS or DTR pin in
automatic 9-bit mode.
RS485 RTS/DTR. Select RTS or DTR pin to control the external
transceiver.
TXDisable. Disable transmitter
RXDisable. Disable receiver
9-bitMode. Enable 9-bit mode or Multidrop (RS-485) mode
logic 0 = RTS or DTR is set to 0 by the UART during transmission,
and to 1 during reception
logic 1 = RTS or DTR is set to 1 by the UART during transmission,
and to 0 during reception
logic 0 = transmitter does not control RTS or DTR pin
logic 1 = transmitter controls RTS or DTR pin
logic 0 = RTS pin is used to control the external transceiver
logic 1 = DTR pin is used to control the external transceiver
logic 0 = transmitter is enabled
logic 1 = transmitter is disabled
logic 0 = receiver is enabled
logic 1 = receiver is disabled
logic 0 = normal RS-232 mode
logic 1 = enable 9-bit mode
Description
External RS-485 transceiver turn-around time delay. The value
represents the bit time at the programmed baud rate.
SC16C850
© NXP B.V. 2008. All rights reserved.
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