参数资料
型号: XR20V2172L64-0B-EB
厂商: Exar Corporation
文件页数: 17/51页
文件大小: 0K
描述: EVAL BOARD FOR XR20V2170 64QFN
标准包装: 1
系列: *
XR20V2172
24
TWO CHANNEL I2C/SPI UART WITH 64-BYTE FIFO AND RS232 TRANSCEIVER
REV. 1.0.2
4.3.1
IER versus Receive FIFO Interrupt Mode Operation
When the receive FIFO (FCR BIT-0 = 1) and receive interrupts (IER BIT-0 = 1) are enabled, the RHR interrupts
(see ISR bits 2 and 3) status will reflect the following:
A. The receive data available interrupts are issued to the host when the FIFO has reached the programmed
trigger level. It will be cleared when the FIFO drops below the programmed trigger level.
B. FIFO level will be reflected in the ISR register when the FIFO trigger level is reached. Both the ISR register
status bit and the interrupt will be cleared when the FIFO drops below the trigger level.
C. The receive data ready bit (LSR BIT-0) is set as soon as a character is transferred from the shift register to
the receive FIFO. It is reset when the FIFO is empty.
4.3.2
IER versus Receive/Transmit FIFO Polled Mode Operation
When FCR BIT-0 equals a logic 1 for FIFO enable; resetting IER bits 0-3 enables the XR20V2172 in the FIFO
polled mode of operation. Since the receiver and transmitter have separate bits in the LSR either or both can
be used in the polled mode by selecting respective transmit or receive control bit(s).
A. LSR BIT-0 indicates there is data in RHR or RX FIFO.
B. LSR BIT-1 indicates an overrun error has occurred and that data in the FIFO may not be valid.
C. LSR BIT 2-4 provides the type of receive data errors encountered for the data byte in RHR, if any.
D. LSR BIT-5 indicates THR is empty.
E. LSR BIT-6 indicates when both the transmit FIFO and TSR are empty.
F. LSR BIT-7 indicates a data error in at least one character in the RX FIFO.
IER[0]: RHR Interrupt Enable
The receive data ready interrupt will be issued when RHR has a data character in the non-FIFO mode or when
the receive FIFO has reached the programmed trigger level in the FIFO mode.
Logic 0 = Disable the receive data ready interrupt (default).
Logic 1 = Enable the receiver data ready interrupt.
IER[1]: THR Interrupt Enable
This bit enables the Transmit Ready interrupt which is issued whenever the THR becomes empty in the non-
FIFO mode or when spaces in the FIFO is above the programmed trigger level in the FIFO mode. If the THR is
empty when this bit is enabled, an interrupt will be generated.
Logic 0 = Disable Transmit Ready interrupt (default).
Logic 1 = Enable Transmit Ready interrupt.
IER[2]: Receive Line Status Interrupt Enable
If any of the LSR register bits 1, 2, 3, 4 or 7 is a logic 1, it will generate an interrupt to inform the host controller
about the error status of the current data byte in FIFO. LSR bit-1 generates an interrupt immediately when the
character has been received. LSR bit-7 is set if any character in the RX FIFO has a parity or framing error, or is
a break character. LSR[4:2] always show the error status for the received character available for reading from
the RX FIFO. If IER[2] = 1, an LSR interrupt will be generated as long as LSR[7] = 1, ie. the RX FIFO contains
at lease one character with an error.
Logic 0 = Disable the receiver line status interrupt (default).
Logic 1 = Enable the receiver line status interrupt.
IER[3]: Modem Status Interrupt Enable
Logic 0 = Disable the modem status register interrupt (default).
Logic 1 = Enable the modem status register interrupt.
相关PDF资料
PDF描述
UPM1E181MPD6TD CAP ALUM 180UF 25V 20% RADIAL
AQ1051N8S-T INDUCTOR 1.8NH 760MA 0402 SMD
UPS2G3R3MPD1TD CAP ALUM 3.3UF 400V 20% RADIAL
XR20V2172L64-0A-EB EVAL BOARD FOR XR20V2170 64QFN
UPJ1C331MPD6TD CAP ALUM 330UF 16V 20% RADIAL
相关代理商/技术参数
参数描述
XR-210 制造商:EXAR 制造商全称:EXAR 功能描述:FSK MODULATOR / DEMODULATOR
XR-2100CJ 制造商:未知厂家 制造商全称:未知厂家 功能描述:MODEM
XR-2100CP 制造商:未知厂家 制造商全称:未知厂家 功能描述:MODEM
XR-2103 制造商:EXAR 制造商全称:EXAR 功能描述:FSK Modem Filter
XR-2103A 制造商:EXAR 制造商全称:EXAR 功能描述:FSK Modem Filter