57 58. dma канали. dma процес и dma контролери

Click here to load reader

Post on 27-Jun-2015

205 views

Category:

Documents

6 download

Embed Size (px)

TRANSCRIPT

  • 1. DMA . DMA DMA . 1.1 (DMA). - , (DMA Direct Memory Access). , , . DMA : , SCSI , , , ISDN . - . , ( ) , . - , DMA . DMA , . , DMA, : - ; , .. , . , DMA, . DMA 6 - , -, 486 - Polling. , (64 128 KByte ISA), .

2. 1.2 DMA DMA : ; ; , . ; , ; , ; , ; , . .1 DMA. . 1 DMA 1.3 DMA IBM-PC 8237 Intel, 4 . 2 8 , . , DMA , . DMA , , PC (). PC DMA. DMA , , ISA . , ATA/IDE , , DMA . 3. DMA ATA/IDE DMA Ultra DMA . DMA 8- ISA 8- ISA 4 DMA , / . . 1 DMA . 1 DMA 8- ISA DMA 0 RAM 1 (8-bit) 2 (8-bit) 3 (8-bit) 0 DMA RAM. , , 8- DMA . DMA 16- ISA 286, ISA DMA , . IRQ , DMA DMA . DMA 4 0 3 . 2 DMA . 2 DMA 16- ISA DMA 0 16-bit 8-bit 1 8/16-bit 8-bit 2 8/16-bit 8-bit 3 8/16-bit 8-bit LPT1: ECP 4 16-bit 4. 2 DMA 16- ISA DMA DMA 5 16-bit 16-bit 6 16-bit 16-bit 7 16-bit 16-bit PC 286 RAM , .. DMA 0 . DMA , , DMA 2, . DMA 1 5 - ISA - Sound Blaster 16 - - PCI , - . 8-, 16- DMA . 0 3 8- , 64 KByte. 5 7 16- , 128 Kbyte . 16- 3, - . DMA , . DMA 7, EIDE 5. DMA IO1 , BIOS-Setup PC. DMA, , , PC ISA DRQx und DACKx ( DMA). DRQ DMA ReQuest - DMA, . DACK DMA ACKnowledge - . DMA, , , - . DRQ0 -, a DRQ7 - - . 1 PIO / . - PIO 0, - 4. - UltraDMA 5. PCI PCI DMA, a (Burst) , . DMA ISA. ISA PCI DMA . , PCI (bus mastering) . - PCI PCI ( ), , . 1.4 DMA . 1.4.1 DMA 8237 . 4 - . 64 . DMA : (Program Condition) DMA. 1.4.2 DMA 3 , 344 (. 2). 6. . 2 DMA 8237 DMA . CLK . : . , . 7 : SI, S0, S1, S2, S3, S4 SW. () SI. DMA , SI, , . (DMA ) S0 , (acknowledge). , . DMA S1, S2, S3 S4. - , S2 S3 S4 SW (Ready). . . 8 : S11, S12, S13 S14; S21, S22, S23 S24. 7. , DMA DMA . DMA , . 8237 , : ( ). , (. 0, - 3). , , - . . , , 3 - . 16- : ; ; (); (), 6- . , DMA . ( 1) ( 1) . 8- . , . ( 1) . , TC (Termimal Count ). () () . . , , . 0 1 , 6 : - (), I/O ; I/O; ; - / ; - ; - : (demand); (single); ; 8. , DMA : - 8- . Reset. 0 1 : ; 0; ; ; ; ; DREQ (DMA Request DMA ) DACK (DMA Acknowledge DMA ). Reset DREQ , DACK . (4-) , / . , TC EOP. (4-) , 1 () () DREQ . : (Terminal Count - TC) DMA . . , , . , , Reset. 1.4.3 . 3. 8237/8237-2 VCC- +5V Vss - 9. CLK (Clock Input ): DMA . /CS2 (Chip Select ): , - . . Reset (): , , , . / / . Reset . Ready (): , , / DREQ0-DREQ3: , . DREQ DACK. DACK0- DACK 3 (DMA Acknowledge - DMA): , DMA . . HRQ (Hold Request - ): , DMA . , DREQ 8237 HRQ. HRQ , HLDA. HLDA (Hold Acknowledge ): , DB0-DB7 (Data Bus Lines ): , . I/O , , , . I/O , , , . DMA - 8 , () ADSTB (Address Strobe). , 8237 . . 2 / , . , , . . , . ( ) - . 10. /IOR (IO Read /): 3 . , CPU . , DMA DMA . /IOW (IO Write /): . , CPU . , DMA DMA . /EOP (End of Process ): . ( TC). DMA , DMA , , . 0-3 ( ): 4 . . 4 . A4-A7 ( ): 4 DMA , 4 . AEN (Address Enable - ): 8- , 8 . AEN DMA . ADSTB (Address Strobe 4 ): . /MEMR (Memory Read- ): , () DMA . /MEMW (Memory Write ): , , DMA . 3 3 (3-state) , (), . , . , 0 1, . ( ). 4 , , , . 11. 1.4.4 , DMA , 8237 "SI" . 8237 DREQ , DMA . CS ( ), 8237. CS HRQ , 8237 (Program Condition). , . A0-A3 . /IOR /IOW . , (-), . 16- . Master Clear Reset. DMA , DREQ. , - . DRQO -, a DRQ3 DRQ7 - . 8237 DMA , HRQ (Hold Request) . HLDA (Hold Acknowledge ), , . DMA , DMA, . DMA : ; ; ; . (Demand Transfer Mode) , DRQ /, DMA - . I/O . (Single) . DREQ ( 512 ), TC (Termimal Count ), , 12. (EOP End Of Process). DMA . 8 , 8 - . 8- 8282, 16 . 8282 , 8-, 3 , 20- . , . : (Read), (Write) (Verify). ( - ) . DMA /MEMW - , /IOR - . /DACK (DMA Acknowledge) , . , - . () , /MEMR /IOW. , , - . , DMA , - , AEN . AEN - . , (memory-to-memory). () . 0 1 . DREQ 0. 8237 DMA . HLDA , 8 , . 0 . , , . 1 , , . 1. 1 , TC, 13. /EOP, . 0 . . 8237 /EOP . , , .