jlmao-微機(jī)原理-ch9-并行接口-part1

1、Kunming University of Science & TechnologyPage 2Kunming University of Science & TechnologyPage 3Kunming University of Science & TechnologyPage 4Kunming University of Science & TechnologyPage 5Kunming University of Science & TechnologyPage 6Kunming University of Science & Tech

2、nologyPage 7Kunming University of Science & TechnologyPage 8Kunming University of Science & TechnologyPage 9Kunming University of Science & TechnologyPage 10D0D7RDWRA1A0RESETCSPA0PA7PB0PB7PC0PC7PA7PA0PB7PB0PC7PC0D7D08255AKunming University of Science & TechnologyPage 11Kunming Univer

3、sity of Science & TechnologyPage 12Kunming University of Science & TechnologyPage 13Kunming University of Science & TechnologyPage 14Kunming University of Science & TechnologyPage 15Kunming University of Science & TechnologyPage 16Kunming University of Science & TechnologyPag

4、e 17Kunming University of Science & TechnologyPage 18Kunming University of Science & TechnologyPage 19Kunming University of Science & TechnologyPage 20Kunming University of Science & TechnologyPage 21Kunming University of Science & TechnologyPage 22Kunming University of Science &

5、amp; TechnologyPage 23Kunming University of Science & TechnologyPage 24Kunming University of Science & TechnologyPage 258255APC5Kunming University of Science & TechnologyPage 26Kunming University of Science & TechnologyPage 27Kunming University of Science & TechnologyPage 28Kunmi

6、ng University of Science & TechnologyPage 29Kunming University of Science & TechnologyPage 30n 設(shè)設(shè)8255A的控制字寄存器的端口地址為的控制字寄存器的端口地址為63H，若要，若要求求A口和口和B口工作于方式口工作于方式0，A口、口、B口和口和C口的上半口的上半部分部分(高高4位位)作輸入，作輸入，C口的下半部分口的下半部分(低低4位位)為輸為輸出，可用下列指令來(lái)設(shè)置：出，可用下列指令來(lái)設(shè)置：MOV AL, 10011010BOUT 63H, ALKunming University

7、of Science & TechnologyPage 31Kunming University of Science & TechnologyPage 32Kunming University of Science & TechnologyPage 33n A口和口和B口都工作于選通輸入方式，口都工作于選通輸入方式，n 注意：注意：uPC3- PC5作為作為PA口的握手信號(hào)口的握手信號(hào)uPC0- PC2作為作為PB口的握手信號(hào)口的握手信號(hào)uPC6,PC7作輸入作輸入/輸出，由方式選擇控制字中的輸出，由方式選擇控制字中的D3定義定義Kunming University

8、of Science & TechnologyPage 34n A口和口和B口都工作于選通輸入方式口都工作于選通輸入方式, 則它們的端口狀則它們的端口狀態(tài)、聯(lián)絡(luò)信號(hào)和控制字如圖所示。態(tài)、聯(lián)絡(luò)信號(hào)和控制字如圖所示。PC3PC5PC4PA7-PA0PC6,PC7STBAINTRAI/OIBFAINTEAPC0PC1PC2PB7-PB0STBBINTRBIBFBINTEB8bit8bitRDRD選通信號(hào)，低電平有效，選通信號(hào)，低電平有效，由外部輸入由外部輸入輸入緩沖器滿信號(hào)，高電平有效。輸入緩沖器滿信號(hào)，高電平有效。中斷請(qǐng)求信號(hào)。中斷請(qǐng)求信號(hào)。中斷允中斷允許信號(hào)許信號(hào)由由PC4控制控制中斷允

9、中斷允許信號(hào)許信號(hào)由由PC2控制控制Kunming University of Science & TechnologyPage 35Kunming University of Science & TechnologyPage 36Kunming University of Science & TechnologyPage 37向向CPU申請(qǐng)中斷申請(qǐng)中斷通知外設(shè)通知外設(shè)BUF已滿已滿撤銷撤銷INTR信號(hào)信號(hào)IBFINTRRDInput from PeripheralSTB此時(shí)此時(shí)INTE = 1數(shù)據(jù)已到端口數(shù)據(jù)已到端口CPU從鎖存器中讀走數(shù)據(jù)從鎖存器中讀走數(shù)據(jù)BUFFE

10、R空空輸入數(shù)據(jù)輸入數(shù)據(jù)123458255A鎖存外設(shè)數(shù)據(jù)鎖存外設(shè)數(shù)據(jù)Kunming University of Science & TechnologyPage 38例：如例：如8255A的端口地址分別為的端口地址分別為60H、61H、62H、63H，把，把8255A設(shè)定設(shè)定為方式為方式1選通輸入方式：選通輸入方式：PA口、口、PB口均允許中斷，口均允許中斷，PC6、PC7為輸出，為輸出，其初始化的程序段為：其初始化的程序段為： MOV AL，10110110B；8255A為方式為方式1選通輸入選通輸入OUT 63H，AL；PC6 PC7為輸出為輸出MOV AL，00001001B；PC

11、4=1, PA端口允許中斷端口允許中斷OUT 63H，ALMOV AL，00000101B；PC2=1, PB端口允許中斷端口允許中斷OUT 63H，ALn 如要讀取如要讀取PA口緩沖器中的數(shù)據(jù)：口緩沖器中的數(shù)據(jù)： n INAL，60Hn 如要讀取如要讀取PB口緩沖器中的數(shù)據(jù)：口緩沖器中的數(shù)據(jù)： n INAL，61HKunming University of Science & TechnologyPage 39，n 注意：注意：uPC3、PC6、PC7作為作為PA口的握手信號(hào)口的握手信號(hào)uPC0、PC1、 PC2作為作為PB口的握手信號(hào)口的握手信號(hào)uPC4,PC5作輸入作輸入/輸出，

12、則由方式選擇控制字中的輸出，則由方式選擇控制字中的D3定定義義Kunming University of Science & TechnologyPage 40PC3PC7PC6PA7-PA0PC5,PC4ACKAINTRAI/OOBFAINTEAPC0PC1PC2PB7-PB0ACKBINTRBOBFBINTEB8bit8bitWRWR選通輸出方式選通輸出方式中斷允中斷允許信號(hào)許信號(hào)由由PC6控制控制中斷允中斷允許信號(hào)許信號(hào)由由PC2控制控制Kunming University of Science & TechnologyPage 41Kunming University

13、of Science & TechnologyPage 42Kunming University of Science & TechnologyPage 43ACK回到高電平回到高電平方式方式1 選通輸出時(shí)序選通輸出時(shí)序撤銷撤銷INTR信號(hào)信號(hào)外設(shè)取走數(shù)據(jù)外設(shè)取走數(shù)據(jù), 應(yīng)答應(yīng)答B(yǎng)UFFER空空INTE = 1新中斷申請(qǐng)新中斷申請(qǐng)8255A通知外設(shè)取數(shù)據(jù)通知外設(shè)取數(shù)據(jù)OBFINTRACKOUTPUTWR輸出數(shù)據(jù)輸出數(shù)據(jù)1234568255A提出中斷申請(qǐng)，提出中斷申請(qǐng)，CPU輸出數(shù)據(jù)到輸出數(shù)據(jù)到8255AKunming University of Science & Te

14、chnologyPage 44PC6=1, PC2=1, Kunming University of Science & TechnologyPage 45，n 注意：注意：uPC3、PC4、 PC5 作為作為PA口的握手信號(hào)口的握手信號(hào)uPC0 、PC1、 PC2 作為作為PB口的握手信號(hào)口的握手信號(hào)uPC6,PC7作輸入作輸入/輸出，由方式選擇控制字中的輸出，由方式選擇控制字中的D3定義定義Kunming University of Science & TechnologyPage 46信號(hào)定義與工作信號(hào)定義與工作過(guò)程與前相類似過(guò)程與前相類似不再贅述不再贅述PA端口選通輸入

15、端口選通輸入PB端口選通輸出端口選通輸出PA7-PA0PC6,PC7IBFAINTRAI/OSTBAACKBINTRBOBFBPB7-PB0PC4 PC5PC3PC2 PC1PC08bit8bitRDWRKunming University of Science & TechnologyPage 47n 注意：注意：uPC3、PC6、PC7作為作為PA口的握手信號(hào)口的握手信號(hào)uPC0、PC1、 PC2作為作為PB口的握手信號(hào)口的握手信號(hào)uPC4,PC5作輸入作輸入/輸出，由方式選擇控制字中的輸出，由方式選擇控制字中的D3定義定義Kunming University of Science

16、 & TechnologyPage 48信號(hào)定義與工作信號(hào)定義與工作過(guò)程與前相類似過(guò)程與前相類似不再贅述不再贅述PA端口選通輸出端口選通輸出PB端口選通輸入端口選通輸入PA7-PA0PC4,PC5OBFAINTRAI/OACKASTBBINTRBIBFBPB7-PB0PC6 PC7PC3PC2 PC1PC08bit8bitWRRDKunming University of Science & TechnologyPage 49Kunming University of Science & TechnologyPage 50Kunming University of Sc

17、ience & TechnologyPage 51【注意注意】1. PC3 PC7作為作為PA口的握手信號(hào)口的握手信號(hào)2. PC2 PC0作為作為PB口的握手信號(hào)，并則由方式選擇口的握手信號(hào)，并則由方式選擇控制字中的控制字中的D0定義定義Kunming University of Science & TechnologyPage 52RDWRPC3PA7-PA0PC2 - 0ACKAINTRAI/OINTE2STBAIBFAOBFAPC4PC5PC7PC6INTE18bitPC6的引腳用于的引腳用于PA口口的的ACKA，而，而PC6的位的位用作用作INTE1PC4的引腳用于的引

18、腳用于PA口口的的STBB，而，而PC4的位的位用作用作INTE2 Kunming University of Science & TechnologyPage 53PA7-PA0ACKAINTRAI/OOBFASTBAPC2 - 0IBFAPC3PC7 PC6 PC5 PC4PB7-PB08bit8bitRDWRKunming University of Science & TechnologyPage 54PA7-PA0INTRAOBFAACKAPC2PC1PC0IBFASTBAPC3PC7 PC6 PC5 PC4PB7-PB08bit8bitSTBBIBFBINTRBRDWRKunming University of Science & TechnologyPage 558bitPA7-PA0INTRAOBFAACKAPC2PC1PC0IBFASTBAPC3PC7 PC6 PC5 PC4PB7-PB08bitACKBINTRBOBFBRDWRKunming Un