SC16C554 Philips Semiconductors, SC16C554 Datasheet - Page 33

• Manufacturer Part Number: SC16C554
• Description: Quad UART with 16-byte FIFO and infrared (IrDA) encoder/decoder
• Manufacturer: Philips Semiconductors

Philips Semiconductors
9397 750 13132
Product data
7.10 Enhanced Feature Register (EFR)
7.9 Scratchpad Register (SPR)
Table 20:
[1]
The SC16C554/554D provides a temporary data register to store 8 bits of user
information.
Enhanced features are enabled or disabled using this register.
Bits 0 through 4 provide single or dual character software flow control selection.
When the Xon1 and Xon2 and/or Xoff1 and Xoff2 modes are selected, the double
8-bit words are concatenated into two sequential numbers.
Table 21:
Bit
1
0
Bit
7
6
Whenever any MSR bit 0-3 is set to logic 1, a Modem Status Interrupt will be generated.
Symbol
MSR[1]
MSR[0]
Symbol
EFR[7]
EFR[6]
Modem Status Register bits description
Enhanced Feature Register bits description
Quad UART with 16-byte FIFO and infrared (IrDA) encoder/decoder
Description
Description
Auto CTS. Automatic CTS Flow Control.
Auto RTS. Automatic RTS may be used for hardware flow control by
enabling EFR[6]. When Auto RTS is selected, an interrupt will be
generated when the receive FIFO is filled to the programmed trigger
level and RTS will go to a logic 1 at the next trigger level. RTS will return
to a logic 0 when data is unloaded below the next lower trigger level.
The state of this register bit changes with the status of the hardware flow
control. RTS functions normally when hardware flow control is disabled.
Rev. 05 — 10 May 2004
DSR
CTS
Logic 0 = No DSR change (normal default condition).
Logic 1 = The DSR input to the SC16C554/554D has changed state
since the last time it was read. A modem Status Interrupt will be
generated.
Logic 0 = No CTS change (normal default condition).
Logic 1 = The CTS input to the SC16C554/554D has changed state
since the last time it was read. A modem Status Interrupt will be
generated.
Logic 0 = Automatic CTS flow control is disabled (normal default
condition).
Logic 1 = Enable Automatic CTS flow control. Transmission will stop
when CTS goes to a logical 1. Transmission will resume when the CTS
pin returns to a logical 0.
Logic 0 = Automatic RTS flow control is disabled (normal default
condition).
Logic 1 = Enable Automatic RTS flow control.
[1]
[1]
…continued
SC16C554/554D
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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