看板 Electronics 關於我們 聯絡資訊
各位好,小弟目前在看David E.Simon的 An Embedded Software Primer一書,遇到幾個看 不懂的地方想要請教 圖片1:http://imgur.com/a/6raMt 圖片2:http://imgur.com/a/6XaKz 圖片3:http://imgur.com/a/BLsyf 圖片4:http://imgur.com/a/3jr39 Q1:請問在第1張圖片中,"A READ/ line, which it pulses or strobes low when it want to get data, and a WRITE/ line, which it pulses low when it want to write data out",strobe low是什麼意思? Q2:一樣在第1張,"A clock signal input, which paces all of the work....",pace all of the work是什麼意思? Q3: 在第2張中,我知道memory address space是什麼,就是可以拉到其他的chip然後提供 其他chip address,那它跟I/O address space差在哪裡呢? 換句話說,我也可以把連到 I/O address space的chip改成連到memory address space。從這本書的內文我看不出來這 兩個之間的差異。 Q4: 在第2張下面跟第3張第一句,"電路圖右上角的gate that drives the memory enable signal(MEMEN/) asserts that signal low when the I/O signal and A19 are both low. This enables the memory chips in the memory address space in the range from 0x00000 to 0x7ffff",我不懂為什麼I/O signal跟A19為LOW時(此時MEMEN/輸出low) 會讓memory address sapce的range為0x00000~0x7ffff Q5: 在第4張圖中,"Note that since this circuit asserts DV1's chip enable signal whenever A19 and I/O are high and does not check A18 through A8, the circuit can read from or write to DV1 no matter what the values of those address signals",請問,CPU只有A0~A15,為什麼會有到A18?還是這張圖畫錯了,是A0~A18? -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 60.248.26.157 ※ 文章網址: https://www.ptt.cc/bbs/Electronics/M.1503024793.A.8DB.html
letitgo02: 沒其他意思,建議把大學的邏輯設計在看一遍 08/20 22:44
yudofu: 建議你先看嵌入式系統的書 08/21 11:24