XR16M570
34
1.62V TO 3.63V HIGH PERFORMANCE UART WITH 16-BYTE FIFO REV. 1.0.1
4.9 Modem Status Register (MSR) - Read Only
This register provides the current state of the modem interface input signals. Lower four bits of this register are
used to indicate the changed information. These bits are set to a logic 1 whenever a signal from the modem
changes state. These bits may be used for general purpose inputs when they are not used with modem
signals. Reading the higher four bits shows the status of the modem signals.
MSR[0]: Delta CTS# Input Flag
Logic 0 = No change on CTS# input (default).
Logic 1 = The CTS# input has changed state since the last time it was monitored. A modem status interrupt
will be generated if MSR interrupt is enabled (IER bit-3).
MSR[1]: Delta DSR# Input Flag
Logic 0 = No change on DSR# input (default).
Logic 1 = The DSR# input has changed state since the last time it was monitored. A modem status interrupt
will be generated if MSR interrupt is enabled (IER bit-3).
MSR[2]: Delta RI# Input Flag
Logic 0 = No change on RI# input (default).
Logic 1 = The RI# input has changed from LOW to HIGH, ending of the ringing signal. A modem status
interrupt will be generated if MSR interrupt is enabled (IER bit-3).
MSR[3]: Delta CD# Input Flag
Logic 0 = No change on CD# input (default).
Logic 1 = Indicates that the CD# input has changed state since the last time it was monitored. A modem
status interrupt will be generated if MSR interrupt is enabled (IER bit-3).
MSR[4]: CTS Input Status
CTS# pin may function as automatic hardware flow control signal input if it is enabled and selected by Auto
CTS (EFR bit-7). Auto CTS Flow Control allows starting and stopping of local data transmissions based on the
modem CTS# signal. A HIGH on the CTS# pin will stop UART transmitter as soon as the current character has
finished transmission, and a LOW will resume data transmission. Normally MSR bit-4 bit is the complement of
the CTS# input. However in the loopback mode, this bit is equivalent to the RTS# bit in the MCR register. The
CTS# input may be used as a general purpose input when the modem interface is not used.
MSR[5]: DSR Input Status
Normally this bit is the complement of the DSR# input. In the loopback mode, this bit is equivalent to the DTR#
bit in the MCR register. The DSR# input may be used as a general purpose input when the modem interface is
not used.
MSR[6]: RI Input Status
Normally this bit is the complement of the RI# input. In the loopback mode this bit is equivalent to bit-2 in the
MCR register. The RI# input may be used as a general purpose input when the modem interface is not used.
MSR[7]: CD Input Status
Normally this bit is the complement of the CD# input. In the loopback mode this bit is equivalent to bit-3 in the
MCR register. The CD# input may be used as a general purpose input when the modem interface is not used.
XR16M570
35
REV. 1.0.1 1.62V TO 3.63V HIGH PERFORMANCE UART WITH 16-BYTE FIFO
4.10 Modem Status Register (MSR) - Write Only
This register provides the advanced features of XR16M570. Lower four bits of this register are reserved.
Writing to the higher four bits enables additional functions.
MSR[3:0]: Reserved
MSR[4]: Enable/Disable Transmitter (Requires EFR[4] = 1)
Logic 0 = Enable Transmitter (default).
Logic 1 = Disable Transmitter.
MSR[5]: Enable/Disable Receiver (Requires EFR[4] = 1)
Logic 0 = Enable Receiver (default).
Logic 1 = Disable Receiver.
MSR[6]: Enable/Disable 9-bit mode (Requires EFR[4] = 1)
For the 9-bit mode information, See ”Section 2.15, Normal Multidrop Mode” on page 18.
Logic 0 = Normal 8-bit mode (default).
Logic 1 = Enable 9-bit or Multidrop mode.
MSR[7]: Enable/Disable fast IR mode (Requires EFR[4] = 1)
The M570 supports the new fast IR transmission with data rate up to 1.152 Mbps.
Logic 0 = IrDA version 1.0, 3/16 pulse ratio, data rate up to 115.2 Kbps (default).
Logic 1 = IrDA version 1.1, 1/4 pulse ratio, data rate up to 1.152 Mbps. For more IR mode information, please
See ”Section 2.16, Infrared Mode” on page 19.
4.11 Scratch Pad Register (SPR) - Read/Write
This is a 8-bit general purpose register for the user to store temporary data. The content of this register is
preserved during sleep mode but becomes 0xFF (default) after a reset or a power off-on cycle.
4.12 Enhanced Mode Select Register (EMSR) - Write-only
This register replaces SPR (during a Write) and is accessible only when FCTR[6] = 1.
EMSR[1:0]: Receive/Transmit FIFO Level Count
When Scratchpad Swap (FCTR[6]) is asserted, EMSR bits 1-0 controls what mode the FIFO Level Counter is
operating in.
During Alternate RX/TX FIFO Level Counter Mode, the first value read after EMSR bits 1-0 have been
asserted will always be the RX FIFO Level Counter. The second value read will correspond with the TX FIFO
Level Counter. The next value will be the RX FIFO Level Counter again, then the TX FIFO Level Counter and
so on and so forth.
T
ABLE 12: SCRATCHPAD SWAP SELECTION
FCTR[6] EMSR[1] EMSR[0]
Scratchpad is
0X X
Scratchpad
1X 0
RX FIFO Level Counter Mode
10 1
TX FIFO Level Counter Mode
11 1
Alternate RX/TX FIFO Counter Mode
XR16M570
36
1.62V TO 3.63V HIGH PERFORMANCE UART WITH 16-BYTE FIFO REV. 1.0.1
EMSR[2]: Send TX Immediately
Logic 0 = Do not send TX immediately (default).
Logic 1 = Send TX immediately. When FIFO is enabled and this bit is set, the next data will be to the TX shift
register. Thus, the data will be sent out immediately instead of queuing in the FIFO. Every time, only 1 byte
will be send out. Once this byte has been sent out, the EMSR[2] will go back to 0 automatically. If more than
1 byte will be sent out, EMSR[2] needs to be set to 1 for each byte.
EMSR[3]: Invert RTS in RS485 mode
Logic 0 = RTS# output is a logic 0 during TX and a logic 1 during RX (default).
Logic 1 = RTS# output is a logic 1 during TX and a logic 0 during RX.
EMSR[5:4]: Reserved
EMSR[6]: LSR Interrupt Mode
Logic 0 = LSR Interrupt Delayed (default). LSR bits 2, 3, and 4 will generate an interrupt when the character
with the error is in the RHR.
Logic 1 = LSR Interrupt Immediate. LSR bits 2, 3, and 4 will generate an interrupt as soon as the character is
received into the FIFO.
EMSR[7]: Xoff/Special character Interrupt Mode Select
This bit selects how the Xoff and Special character interrupt is cleared. The XON interrupt can only be cleared
by reading the ISR register.
Logic 0 = Xoff interrupt is cleared by either reading ISR register or when an XON character is received.
Special character interrupt is cleared by either reading ISR register or when next character is received.
(default).
Logic 1 = Xoff/Special character interrupt can only be cleared by reading the ISR register.
4.13 Baud Rate Generator Registers (DLL, DLM and DLD) - Read/Write
These registers make-up the value of the baud rate divisor. The M570 has different DLL, DLM and DLD for
transmitter and receiver. It provides more convenience for the transmitter and receiver to transmit data with
different rate. The M570 uses DLD[7:6] to select TX or RX. Then it provides DLD[5:0] to select the sampling
frequency and fractional baud rate divisor. The concatenation of the contents of DLM and DLL gives the 16-bit
divisor value. The value is added to DLD[3:0]/16 to achieve the fractional baud rate divisor. DLD must be
enabled via EFR bit-4 before it can be accessed. See Table 13 below and See ”Section 2.7, Programmable
Baud Rate Generator with Fractional Divisor” on page 11.
DLD[5:4]: Sampling Rate Select
These bits select the data sampling rate. By default, the data sampling rate is 16X. The maximum data rate will
double if the 8X mode is selected and will quadruple if the 4X mode is selected. See Table 13 below.
T
ABLE 13: SAMPLING RATE SELECT
DLD[5] DLD[4] SAMPLING RATE
0016X
018X
1X4X

XR16M570IL24-F

Mfr. #:
Manufacturer:
MaxLinear
Description:
UART Interface IC 1.8 HIGH PERFORMANCE UART W/16
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union