- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄382374 > PC-COM4 PC(ISA)BUS I/O CARD PDF資料下載
參數(shù)資料
| 型號： | PC-COM4 |
| 英文描述： | PC(ISA)BUS I/O CARD |
| 中文描述： | 電腦（ISA）總線的I / O卡 |
| 文件頁數(shù)： | 12/20頁 |
| 文件大?。?/td> | 492K |
| 代理商： | PC-COM4 |
2192-09197-000-000
Page 12
J606 PC-COM4
CONTROL SYSTEMS
Appendix A. Notes on Using the 16C550 UART
Enabling the Interrupt Outputs
If you intend to write your own low level UART handler, it is necessary to remember that in
order for the UART channel on the PC-COM4 to generate interrupts to the host CPU, you must
enable the IRQ output from the UART by setting bit 3 in the Modem Control Register (MRC).
Standard driver software (including that supplied on the library disk with the PC-COM4) will do
this as part of the port initialisation, so no action will be necessary if you are using Arcom’s
software or that of a 3rd. party vendor.
The Receiver FIFO Trigger Point and Timeout
The 16C550 has sixteen byte FIFO’s for both it’s transmit buffer and receive buffer. This can
enhance the performance of the serial ports and reduce the interrupt rate main processor.
However, it is necessary to set up the receive trigger point optically for your application.
With the FIFO enabled, any receive character is added to the 16 byte receive FIFO. This has
four programmable trigger points as shown in the following diagram:
Once the FIFO has received sufficient characters to reach the FIFO trigger point, an interrupt
is generated that is serviced in order to remove all the characters from the FIFO.
If the stream stops adding characters to the FIFO before the trigger point is reached. For
example the trigger may set at eight when only six characters has been received. In this
situation the UART will generate an IRQ after specific timeout period from the end of the last
character received.
The timeout period, expressed in the number of characters can be calculated using the
following equation:
T=
(4 x n
Char
) + 12
(n
Parity
+ n
Char
+ n
Stop
+1)
Where:
n
Char
is the number of programmed bits per character (5, 6, 7 or 8)
n
Parity
is the number of programmed parity bits (1 unless no parity)
n
Stop
is the number of stop bits (1 ,1 or 2)
The actual time for timeout is simply defined as :
t=
(4 x n
Char
) + 12
F
Braud
Where
F
Braud
is the baud rate.
Rx
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16
T14
IRQ
T8
T4
T1
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| PC1231XNSZ | PHOTOCOUPLER |
| PC123 | European Safety Standard Approved Type Long Creepage Distance Photocoupler |
| PC123A | DEVICE SPECIFICATION FOR PHOTOCOUPLER |
| PC123F | European Safety Standard Approved Type Long Creepage Distance Photocoupler |
| PC1316 | Dual Channel Audio Power Amplifier Dual Power Amplifier 2W 12V 10% |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| PCC-OST-E | 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Sta 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Standard Connector, Connector Mounting:PCB, Connector Type:Thermocouple, No. of Contacts:2, Series:PCC, Thermocouple Type:E , RoHS Compliant: NA |
| PCC-OST-K | 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Sta 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Standard Connector, Connector Mounting:PCB, Connector Type:Thermocouple, No. of Contacts:2, Series:PCC, Thermocouple Type:K , RoHS Compliant: NA |
| PCC-OST-T | 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Standard Connector, Connector Mounting:PCB, Connector Type:Thermocouple, No. of Contacts:2, Series:PCC, Thermocouple Type:T , RoHS Compliant: NA |
| PCCOV19001BK1 | 功能描述:機(jī)架和機(jī)柜配件 WIRE MANAGER COVER 1U RoHS:否 制造商:Bivar 產(chǎn)品:Rack Accessories 面板空間: 顏色:Black |
| PCCOV19003BK1 | 功能描述:機(jī)架和機(jī)柜配件 WIRE MANAGER COVER 2U RoHS:否 制造商:Bivar 產(chǎn)品:Rack Accessories 面板空間: 顏色:Black |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。