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參數(shù)資料
型號： W83877AF
廠商： WINBOND ELECTRONICS CORP
元件分類： 外設(shè)及接口
英文描述： Multi-Function I/O Port Controller(多功能輸入／輸出口控制器)
中文描述： MULTIFUNCTION PERIPHERAL, PQFP100
封裝： QFP-100
文件頁數(shù)： 103/171頁
文件大小： 1634K
代理商： W83877AF
W83877AF
Publication Release Date: Dec. 1996
Preliminary Version 0.52
- 101 -
5.3.15 DMA Transfers
DMA transfers are always to or from the ecpDFifo, tFifo, or CFifo. The DMA uses the standard PC
DMA services. The ECP requests DMA transfers from the host by activating the PDRQ pin. The DMA
will empty or fill the FIFO using the appropriate direction and mode. When the terminal count in the
DMA controller is reached, an interrupt is generated and serviceIntr is asserted, which will disable the
DMA.
5.3.16 Programmed I/O (NON-DMA) Mode
The ECP or parallel port FIFOs can also be operated using interrupt driven programmed I/O.
Programmed I/O transfers are to the ecpDFifo at 400H and ecpAFifo at 000H or from the ecpDFifo
located at 400H, or to/from the tFifo at 400H. The host must set the direction, state, dmaEn = 0 and
serviceIntr = 0 in the programmed I/O transfers.
The ECP requests programmed I/O transfers from the host by activating the IRQ pin. The
programmed I/O will empty or fill the FIFO using the appropriate direction and mode.
5.4 Extension FDD Mode (EXTFDD)
In this mode, the W83877AF changes the printer interface pins to FDC input/output pins, allowing the
user to install a second floppy disk drive (FDD B) through the DB-25 printer connector. The pin
assignments for the FDC input/output pins are shown in Table 5-1.
After the printer interface is set to EXTFDD mode, the following occur:
(1) Pins MOB and DSB will be forced to inactive state.
(2) Pins DSKCHG, RDATA, WP, TRAK0, INDEX will be logically ORed with pins PD4-PD0 to
serve as input signals to the FDC.
(3) Pins PD4-PD0 each will have an internal resistor of about 1K ohm to serve as pull-up resistor for
FDD open drain/collector output.
(4) If the parallel port is set to EXTFDD mode after the system has booted DOS or another operating
system, a warm reset is needed to enable the system to recognize the extension floppy drive.
5.5 Extension 2FDD Mode (EXT2FDD)
In this mode, the W83877AF changes the printer interface pins to FDC input/output pins, allowing the
user to install two external floppy disk drives through the DB-25 printer connector to replace internal
floppy disk drives A and B. The pin assignments for the FDC input/output pins are shown in Table 5-
1.
After the printer interface is set to EXTFDD mode, the following occur:
(1) Pins MOA, DSA, MOB, and DSB will be forced to inactive state.
(2) Pins DSKCHG, RDATA, WP, TRAK0, and INDEX will be logically ORed with pins PD4-PD0 to
serve as input signals to the FDC.
(3) Pins PD4-PD0 each will have an internal resistor of about 1K ohm to serve as pull-up resistor for
FDD open drain/collector output.
相關(guān)PDF資料
PDF描述
W83877ATD enhanced version from Winbonds most popular I/O chip W83877F
W83877ATF enhanced version from Winbonds most popular I/O chip W83877F
W83877 WINBOND I/O
W83877F WINBOND I/O
W83877TD I/O chip disk drive adapter
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
W83877ATD 制造商:WINBOND 制造商全稱:Winbond 功能描述:enhanced version from Winbonds most popular I/O chip W83877F
W83877ATF 制造商:WINBOND 制造商全稱:Winbond 功能描述:enhanced version from Winbonds most popular I/O chip W83877F
W83877F 制造商:WINBOND 制造商全稱:Winbond 功能描述:WINBOND I/O
W83877TD 制造商:WINBOND 制造商全稱:Winbond 功能描述:WINBOND I/O
W83877TF 制造商:WINBOND 制造商全稱:Winbond 功能描述:WINBOND I/O
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