executed on " />
參數(shù)資料
型號: 20-101-0788
廠商: Rabbit Semiconductor
文件頁數(shù): 83/90頁
文件大?。?/td> 0K
描述: COMPUTER SGL-BOARD OP6600 W/SRAM
標(biāo)準(zhǔn)包裝: 1
系列: SBC
模塊/板類型: 單板計算機模塊
適用于相關(guān)產(chǎn)品: OP6600
80
Intellicom (OP6600/OP6700)
The statement at (3) waits for a time delay, in this case 200 ms. The costatement is being
executed on each pass through the big loop. When a waitfor condition is encountered
the first time, the current value of MS_TIMER is saved and then on each subsequent pass
the saved value is compared to the current value. If a waitfor condition is not encoun-
tered, then a jump is made to the end of the costatement (4), and on the next pass of the
loop, when the execution thread reaches the beginning of the costatement, execution
passes directly to the waitfor statement. Once 200 ms has passed, the statement after the
waitfor is executed. The costatement has the property that it can wait for long periods of
time, but not use a lot of execution time. Each costatement is a little program with its own
statement pointer that advances in response to conditions. On each pass through the big
loop, as little as one statement in the costatement is executed, starting at the current posi-
tion of the costatement’s statement pointer. Consult the Dynamic C User’s Manual for
more details.
The second costatement in the program debounces the switch and maintains the variable
vswitch
. Debouncing is performed by making sure that the switch is either on or off for a
long enough period of time to ensure that high-frequency electrical hash generated when
the switch contacts open or close does not affect the state of the switch. The abort state-
ment is illustrated at (5). If executed, the internal statement pointer is set back to the first
statement within the costatement, and a jump to the closing brace of the costatement is
made.
At (6) a use for a shadow register is illustrated. A shadow register is used to keep track of
the contents of an I/O port that is write only - it can’t be read back. If every time a write is
made to the port the same bits are set in the shadow register, then the shadow register has
the same data as the port register. In this case a test is made to see the state of the LED and
make it agree with the state of vswitch. This test is not strictly necessary, the output regis-
ter could be set every time to agree with vswitch, but it is placed here to illustrate the con-
cept of a shadow register.
To illustrate the use of snooping, use the watch window to observe vswitch while the
program is running. Add the variable vswitch to the list of watch expressions. Then tog-
gle vswitch and the LED. Then type <ctrl-U> to observe vswitch again.
D.2.3 Advantages of Cooperative Multitasking
Cooperative multitasking, as implemented with language extensions, has the advantage of
being intuitive. Unlike preemptive multitasking, variables can be shared between different
tasks without having to take elaborate precautions. Sharing variables between tasks is the
greatest cause of bugs in programs that use preemptive multitasking. It might seem that
the biggest problem would be response time because of the big loop time becoming long
as the program grows. Our solution for that is a device caused slicing that is further
described in the Dynamic C User’s Manual.
相關(guān)PDF資料
PDF描述
20-101-1068 MODULE RABBITCORE RCM3315
20-101-1131 MODULE RCM4200 RABBITCORE
20-101-1139 RCM4310 RABBITCORE
20-101-1154 MODULE RCM4120 RABBITCORE
20-101-1197 MODULE RABBITCORE RCM3910 ROHS
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
201-0108-01 功能描述:印刷電路板和試驗板 RJ11/45 and USB Connector RoHS:否 制造商:3M Electronic Solutions Division 產(chǎn)品:Jumper & Insulated Wires 描述/功能:Jumper wire, 22 AWG 0.1 inch 長度:0.1 in 寬度:
20-101-0818 功能描述:單板計算機 BL2100 Fric Lk 512K RoHS:否 制造商:Ampro By ADLINK 外觀尺寸:EPIC 處理器類型:Intel Atom D510 頻率:1.66 GHz 存儲容量:2 GB (max) 存儲類型:DDR2, L2 Cache 接口類型:Ethernet, PS/2, SATA, Serial, USB 工作電源電壓:5 V, 12 V 功耗:13 W 最大工作溫度:+ 70 C 尺寸:165.1 mm x 114.3 mm
20-101-0820 功能描述:COMPUTER SGL-BD BL2000 SRAM/FLSH RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器或微處理器模塊 系列:SBC 產(chǎn)品目錄繪圖:DLP-245SY-G 標(biāo)準(zhǔn)包裝:1 系列:USB 模塊/板類型:開發(fā)板 適用于相關(guān)產(chǎn)品:USB 其它名稱:813-1006
20-101-0841 功能描述:模塊化系統(tǒng) - SOM BL2000 FRICT LOCK W/ RoHS:否 制造商:Digi International 外觀尺寸:ConnectCore 9P 處理器類型:ARM926EJ-S 頻率:150 MHz 存儲容量:8 MB, 16 MB 存儲類型:NOR Flash, SDRAM 接口類型:I2C, SPI, UART 工作電源電壓:3.3 V 最大工作溫度:+ 85 C 尺寸:1.97 in x 1.97 in x 6.1 in
20-101-0847 功能描述:模塊化系統(tǒng) - SOM BL2121 LOCK RoHS:否 制造商:Digi International 外觀尺寸:ConnectCore 9P 處理器類型:ARM926EJ-S 頻率:150 MHz 存儲容量:8 MB, 16 MB 存儲類型:NOR Flash, SDRAM 接口類型:I2C, SPI, UART 工作電源電壓:3.3 V 最大工作溫度:+ 85 C 尺寸:1.97 in x 1.97 in x 6.1 in