參數(shù)資料
型號: CD1865
廠商: Intel Corp.
英文描述: Intelligent Eight-Channel Communications Controller
中文描述: 智能八通道通信控制器
文件頁數(shù): 59/150頁
文件大小: 871K
代理商: CD1865
Intelligent Eight-Channel Communications Controller
CD1865
Datasheet
59
An overrun condition occurs when the new data arrives, but the Receive FIFO and the Receive
Holding register are both full. The new data is lost and the overrun indication is flagged on the
character in the Holding register. That character and its status including the overrun indication is
eventually transferred to the host by a Receive Exception Service Request. Note that this character
is good, and is the last character received before the overrun occurred.
Receiver Service Requests are enabled or disabled by the Receive Data bit in the Enable register
(). Receive Data bit, when set to a
1
, enables service requests to be asserted for the above causes.
The Prescaler Period Counter is a 16-bit counter clocked by the system clock. If the system clock is
a 33-MHz clock, the maximum count establishes a clock tick every 1.9859 ms. The Prescaler
Period should be set to generate a minimum tick period of 1.0 ms. The Receive Time-out Counter
is an 8-bit counter decremental on every tick of the Prescaler Period Counter. At the maximum
count per tick, the maximum time-out period is 0.506 seconds.
The Receive Time-out is always enabled to transfer data when the Receive Data Service Request is
enabled. From the system applications view-point, this time-out function is important for
asynchronous data transmission. This is especially true when a FIFO is in use and a service request
threshold for the FIFO is set greater than one character. The Timer Service Request eliminates long
response times when excessive delay between characters occurs caused either by the remote
operator or due to the line being disabled. The
No New Data
Timer Service request, which occurs
after all data is transferred to the host, may be used to manage transfers from the host
s receive data
buffers.
Figure 22. Receive Operation
RECEIVER SHIFT REGISTER
RECEIVER HOLDING REGISTER
FULL/
EMPTY
BIT
RECEIVER
FIFO
RECEIVE DATA COUNT REGISTER
BACKGROUND CODE:
H.R.-TO-FIFO TRANSFER, FLOW
CONTROL, OTHER FEATURES
(POLLING LOOP)
FOREGROUND CODE:
BIT ASSEMBLY,
S.R.-TO-H.R. TRANSFER
(INTERRUPT-DRIVEN)
DTR
OUT
DSR
IN
RECEIVE
STATUS
FIFO
RECEIVER
相關(guān)PDF資料
PDF描述
CD22100 CMOS 4 x 4 Crosspoint Switch with Control Memory High-Voltage Type (20V Rating)
CD22100E CMOS 4 x 4 Crosspoint Switch with Control Memory High-Voltage Type (20V Rating)
CD22100F CMOS 4 x 4 Crosspoint Switch with Control Memory High-Voltage Type (20V Rating)
CD22101 CMOS 4 x 4 x 2 Crosspoint Switch with Control Memory
CD22101E CMOS 4 x 4 x 2 Crosspoint Switch with Control Memory
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
CD1865N 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
CD1865P 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
CD1866N 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
CD1866P 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC
CD1867N 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC