針對目前使用的RS232接口數字化B超鍵盤存在PC主機啟動時不能設置BIOS，提出一種PS2鍵盤的設計方法?；赪78E052D單片機，采用8通道串行A/D轉換器設計了8個TGC電位器信息采集電路，電位器位置信息以鍵盤掃描碼序列形式發送，正交編碼器信號通過XC9536XL轉換為單片機可接收的中斷信號，軟件接收到中斷信息后等效處理成按鍵。結果表明，在滿足開機可設置BIOS同時，又可實現超聲特有功能，不需要專門設計驅動程序，接口簡單，成本低。
Abstract: Aiming at the problem of the digital ultrasonic diagnostic imaging system keyboard with RS232 interface currently used couldn?蒺t set the BIOS when the PC boot， this paper proposed a design method of PS2 keyboards. Based on W78E052D microcontroller，designed eight TGC potentiometers information acquisition circuit with 8-channel serial A/D converter， potentiometer position information sent out with keyboard scan code sequentially.The control circuit based on XC9536 CPLD is used for converting the mechanical actions of the encoders into the signals that can be identified by the MCU， software received interrupt information and equivalently treatmented as key. The results show that the BIOS can be set to meet the boot， ultrasound specific functionality can be achieved at the same time， it does not require specially designed driver，the interface is simple and low cost.
java ejb開發 程序4、語句alter table people add(phone_number varchar2(10)) 的作用是 A 修改表結構 B 為people表添加約束，約束名稱是phone_number C 向people表中添加一列，名稱是phone_number，數據類型是varchar2，長度是10 D 上述答案均不正確 5、（ ）BLOB和CLOB的區別在于 A CLOB只能存放字符類型的數據，而BLOB沒有任何限制 B BLOB只能存放字符類型的數據，而CLOB沒有任何限制 C CLOB只能存放小于4000字節的數據，而BLOB可以存放大于4000字節的數據 D BLOB只能存放小于4000字節的數據，而CLOB可以存放大于4000字節的數據 6、存儲過程從本質上來講就是 A 匿名的PL/SQL程序塊，它可以被賦予參數 B 命名的PL/SQL程序塊，它可以被賦予參數 C 命名的PL/SQL程序塊，不能被賦予參數 D 匿名的PL/SQL程序塊，不能被賦予參數 7、（ ）下列關于日期數據類型，哪一個語句是正確的寫法 A insert into test values( 9999-12-03 ) B insert into test values( 1999-03-02 ) C insert into test values(to_char(1999-06-03, yyyy/dd/mm )) D insert into test
