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REV. 1.0.1 1.62V TO 3.63V HIGH PERFORMANCE UART WITH 16-BYTE FIFO
DLD[6]: Independent BRG enable
Logic 0 = The Transmitter and Receiver uses the same Baud Rate Generator. (default).
Logic 1 = The Transmitter and Receiver uses different Baud Rate Generators. Use DLD[7] for selecting
which baud rate generator to configure.
DLD[7]: BRG select
When DLD[6] = 1, this bit selects whether the values written to DLL, DLM and DLD[5:0] will be for the Transmit
Baud Rate Generator or the Receive Baud Rate Generator. When DLD[6] = 0 (same Baud Rate Generator
used for both TX and RX), this bit must be a logic 0 to properly write to the appropriate DLL, DLM and
DLD[5:0]. .
4.14 RX/TX FIFO Level Count Register (FC) - Read-Only
This register replaces SPR (during a read) and is accessible when FCTR[6] = 1. This register is also
accessible when LCR = 0xBF. It is suggested to read the FIFO Level Count Register at the Scratchpad
Register location when FCTR bit-6 = 1. See Table 12.
FC[7:0]: RX/TX FIFO Level Count
Receive/Transmit FIFO Level Count. Number of characters in Receiver FIFO (FCTR[7] = 0) or Transmitter
FIFO (FCTR[7] = 1) can be read via this register. Reading this register is not recommended when transmitting
or receiving data.
4.15 Feature Control Register (FCTR) - Read/Write
FCTR[1:0]: Reserved
FCTR[2]: IrDa RX Inversion
Logic 0 = Select RX input as encoded IrDa data (Idle state will be LOW).
Logic 1 = Select RX input as inverted encoded IrDa data (Idle state will be HIGH).
FCTR[3]: Auto RS-485 Direction Control
Logic 0 = Standard ST16C550 mode. Transmitter generates an interrupt when transmit holding register
becomes empty and transmit shift register is shifting data out.
Logic 1 = Enable Auto RS485 Direction Control function. The direction control signal, RTS# pin, changes its
output logic state from LOW to HIGH one bit time after the last stop bit of the last character is shifted out.
Also, the Transmit interrupt generation is delayed until the transmitter shift register becomes empty. The
RTS# output pin will automatically return to a LOW when a data byte is loaded into the TX FIFO. However,
RTS# behavior can be inverted by setting EMSR[3] = 1.
FCTR[5:4]: Reserved
T
ABLE 14: BRG SELECT
DLD[7] DLD[6] BRG
0 0 Transmitter and Receiver uses same BRG.
Writing to DLL, DLM and DLD[5:0] configures the BRG for both the TX and RX.
0 1 Transmitter and Receiver uses different BRGs.
Writing to DLL, DLM and DLD[5:0] configures the BRG for TX.
1 1 Transmitter and Receiver uses different BRGs.
Writing to DLL, DLM and DLD[5:0] configures the BRG for RX.
1 0 Transmitter and Receiver uses same BRG.
Writing to DLL, DLM and DLD[5:0] has no effect on BRG used by the TX and RX.
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1.62V TO 3.63V HIGH PERFORMANCE UART WITH 16-BYTE FIFO REV. 1.0.1
FCTR[6]: Scratchpad Swap
Logic 0 = Scratch Pad register is selected as general read and write register. ST16C550 compatible mode.
Logic 1 = FIFO Count register (Read-Only), Enhanced Mode Select Register (Write-Only). Number of
characters in transmit or receive FIFO can be read via scratch pad register when this bit is set. Enhanced
Mode Select Register is selected when it is written into.
FCTR[7]: Programmable Trigger Register Select
Logic 0 = Register FC selected for RX.
Logic 1 = Register FC selected for TX.
4.16 Enhanced Feature Register (EFR) - Read/Write
Enhanced features are enabled or disabled using this register. Bit 0-3 provide single or dual consecutive
character software flow control selection (see Table 15). When the Xon1 and Xon2 and Xoff1 and Xoff2 modes
are selected, the double 8-bit words are concatenated into two sequential characters. Caution: note that
whenever changing the TX or RX flow control bits, always reset all bits back to logic 0 (disable) before
programming a new setting.
EFR[3:0]: Software Flow Control Select
Single character and dual sequential characters software flow control is supported. Combinations of software
flow control can be selected by programming these bits.
T
ABLE 15: SOFTWARE FLOW CONTROL FUNCTIONS
EFR BIT-3
CONT-3
EFR BIT-2
CONT-2
EFR
BIT-1
C
ONT-1
EFR
BIT-0
C
ONT-0
T
RANSMIT AND RECEIVE SOFTWARE FLOW CONTROL
0 0 0 0 No TX and RX flow control (default and reset)
0 0 X X No transmit flow control
1 0 X X Transmit Xon1, Xoff1
0 1 X X Transmit Xon2, Xoff2
1 1 X X Transmit Xon1 and Xon2, Xoff1 and Xoff2
X X 0 0 No receive flow control
X X 1 0 Receiver compares Xon1, Xoff1
X X 0 1 Receiver compares Xon2, Xoff2
1 0 1 1 Transmit Xon1, Xoff1
Receiver compares Xon1 or Xon2, Xoff1 or Xoff2
0 1 1 1 Transmit Xon2, Xoff2
Receiver compares Xon1 or Xon2, Xoff1 or Xoff2
1 1 1 1 Transmit Xon1 and Xon2, Xoff1 and Xoff2,
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2
0 0 1 1 No transmit flow control,
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2
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REV. 1.0.1 1.62V TO 3.63V HIGH PERFORMANCE UART WITH 16-BYTE FIFO
EFR[4]: Enhanced Function Bits Enable
Enhanced function control bit. This bit enables IER bits 4-7, ISR bits 4-5, FCR bits 3-5, MCR bits 5-7, and DLD
to be modified. After modifying any enhanced bits, EFR bit-4 can be set to a logic 0 to latch the new values.
This feature prevents legacy software from altering or overwriting the enhanced functions once set. Normally, it
is recommended to leave it enabled, logic 1.
Logic 0 = modification disable/latch enhanced features. IER bits 4-7, ISR bits 4-5, FCR bits 3-5, MCR bits 5-
7, and DLD are saved to retain the user settings. After a reset, the IER bits 4-7, ISR bits 4-5, FCR bits 3-5,
and MCR bits 5-7, and DLD are set to a logic 0 to be compatible with ST16C550 mode (default).
Logic 1 = Enables the EFR[3:0] register bits to be modified by the user.
EFR[5]: Special Character Detect Enable
Logic 0 = Special Character Detect Disabled (default).
Logic 1 = Special Character Detect Enabled. The UART compares each incoming receive character with
data in Xoff-2 register. If a match exists, the receive data will be transferred to FIFO and ISR bit-4 will be set
to indicate detection of the special character. Bit-0 corresponds with the LSB bit of the receive character. If
flow control is set for comparing Xon1, Xoff1 (EFR [1:0]= ‘10’) then flow control and
special character work
normally. However, if flow control is set for comparing Xon2, Xoff2 (EFR[1:0]= ‘01’) then flow control works
normally, but Xoff2 will not
go to the FIFO, and will generate an Xoff interrupt and a special character
interrupt, if enabled via IER bit-5.
EFR[6]: Auto RTS Flow Control Enable
RTS# output may be used for hardware flow control by setting EFR bit-6 to logic 1. When Auto RTS is
selected, an interrupt will be generated when the receive FIFO is filled to the selected trigger level and RTS de-
asserts HIGH at the next upper trigger level/hysteresis level. RTS# will return LOW when FIFO data falls below
the next lower trigger level/hysteresis level. The RTS# output must be asserted (LOW) before the auto RTS
can take effect. RTS# pin will function as a general purpose output when hardware flow control is disabled.
Logic 0 = Automatic RTS flow control is disabled (default).
Logic 1 = Enable Automatic RTS flow control.
EFR[7]: Auto CTS Flow Control Enable
Automatic CTS Flow Control.
Logic 0 = Automatic CTS flow control is disabled (default).
Logic 1 = Enable Automatic CTS flow control. Data transmission stops when CTS# input de-asserts to logic
1. Data transmission resumes when CTS# returns to a logic 0.
4.17 Software Flow Control Registers (XOFF1, XOFF2, XON1, XON2) - Read/Write
These registers are used as the programmable software flow control characters xoff1, xoff2, xon1, and xon2.
For more details, see Table 5. The xoff2 is also used as auto address detect register when the auto 9-bit mode
enabled. See ”Section 2.15.1, Auto Address Detection” on page 19.

XR16M570IL24-0C-EB

Mfr. #:
Manufacturer:
MaxLinear
Description:
Interface Development Tools Eval Board for XR16M570IL24 Series
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New from this manufacturer.
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