- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄376460 > XRT16L2552 (Exar Corporation) 2.25V TO 5.5V DUART WITH 16-BYTE FIFO PDF資料下載
參數(shù)資料
| 型號： | XRT16L2552 |
| 廠商： | Exar Corporation |
| 英文描述： | 2.25V TO 5.5V DUART WITH 16-BYTE FIFO |
| 中文描述： | 2.25V至5.5V的杜阿爾特16字節(jié)FIFO |
| 文件頁數(shù)： | 17/47頁 |
| 文件大?。?/td> | 413K |
| 代理商： | XRT16L2552 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁當(dāng)前第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁
xr
REV. 1.1.1
XR16L2552
2.25V TO 5.5V DUART WITH 16-BYTE FIFO
17
2.16
When software flow control is enabled (
See Table 12
), the L2552 compares one or two sequential receive data
characters with the programmed Xon or Xoff-1,2 character value(s). If receive character(s) (RX) match the
programmed values, the L2552 will halt transmission (TX) as soon as the current character has completed
transmission. When a match occurs, the Xoff (if enabled via IER bit-5) flag will be set and the interrupt output
pin will be activated. Following a suspension due to a match of the Xoff character, the L2552 will monitor the
receive data stream for a match to the Xon-1,2 character. If a match is found, the L2552 will resume operation
and clear the flags (ISR bit-4).
Reset initially sets the contents of the Xon/Xoff 8-bit flow control registers to a logic 0. Following reset the user
can write any Xon/Xoff value desired for software flow control. Different conditions can be set to detect Xon/
Xoff characters (
See Table 12
) and suspend/resume transmissions. When double 8-bit Xon/Xoff characters are
selected, the L2552 compares two consecutive receive characters with two software flow control 8-bit values
(Xon1, Xon2, Xoff1, Xoff2) and controls TX transmissions accordingly. Under the above described flow control
mechanisms, flow control characters are not placed (stacked) in the user accessible RX data buffer or FIFO.
In the event that the receive buffer is overfilling and flow control needs to be executed, the L2552 automatically
sends an Xoff message (when enabled) via the serial TX output to the remote modem. The L2552 sends the
Xoff-1,2 characters two-character-times (= time taken to send two characters at the programmed baud rate)
after the receive FIFO crosses the programmed trigger level. To clear this condition, the L2552 will transmit the
programmed Xon-1,2 characters as soon as receive FIFO is less than one trigger level below the programmed
trigger level. See
Table 6
below.
Auto Xon/Xoff (Software) Flow Control
*
After the trigger level is reached, an xoff character is sent after a short span of time (= time required to send 2
characters); for example, after 2.083ms has elapsed for 9600 baud and 8-bit word length, no parity and 1 stop bit setting.
2.17
Special Character Detect
A special character detect feature is provided to detect an 8-bit character when bit-5 is set in the Enhanced
Feature Register (EFR). When this character (Xoff2) is detected, it will be placed in the FIFO along with normal
incoming RX data.
The L2552 compares each incoming receive character with Xoff-2 data. If a match exists, the received data will
be transferred to FIFO and ISR bit-4 will be set to indicate detection of special character. Although the Internal
Register Table shows Xon, Xoff Registers with eight bits of character information, the actual number of bits is
dependent on the programmed word length. Line Control Register (LCR) bits 0-1 defines the number of
character bits, i.e., either 5 bits, 6 bits, 7 bits, or 8 bits. The word length selected by LCR bits 0-1 also
determines the number of bits that will be used for the special character comparison. Bit-0 in the Xon, Xoff
Registers corresponds with the LSB bit for the receive character.
T
ABLE
6: A
UTO
X
ON
/X
OFF
(S
OFTWARE
) F
LOW
C
ONTROL
RX T
RIGGER
L
EVEL
INT P
IN
A
CTIVATION
X
OFF
C
HARACTER
(
S
) S
ENT
(
CHARACTERS
IN
RX
FIFO
)
X
ON
C
HARACTER
(
S
) S
ENT
(
CHARACTERS
IN
RX
FIFO
)
1
1
1*
0
4
4
4*
1
8
8
8*
4
14
14
14*
8
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| XRT3591 | SINGLECHIP V. 35 TRANSCEIVER |
| XRT3591B | SINGLECHIP V. 35 TRANSCEIVER |
| XRT3591BID | SINGLECHIP V. 35 TRANSCEIVER |
| XRT3591BIP | SINGLECHIP V. 35 TRANSCEIVER |
| XRT4000 | Universal Multiprotocol Serial Interface |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| XRT2588CN | 制造商:Exar Corporation 功能描述: |
| XR-T2713CP | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Subscriber Line Metering/Monitoring Circuit |
| XR-T3588 | 制造商:EXAR 制造商全稱:EXAR 功能描述:V.35 Interface Receiver/Transmitter |
| XR-T3588-89ES | 制造商:EXAR 制造商全稱:EXAR 功能描述:XR-T3588/89 Evaluation System |
| XRT3588CN | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:IC-INTERFACE TRANSMITTER |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。