ADVANCED VL-IDE DISK CONTROLLER
The W83759A is an advanced version of Winbond's popular VL-IDE interface chip, the W83759. The
W83759A retains all of the features and compatibility of the W83759 (the chip meets the ANSI ATA
4.0 specification for IDE hard disk operation and the VESA VL-Bus 2.0 specification for PC local bus
devices) while incorporating new features to meet Enhanced IDE, SFF-8011, ATA-2, and Fast-ATA
Supports Disk Capacity of Greater than 528 MB
The W83759A's driver can handle remapping from BIOS CHS mode to HDD LBA mode. This scheme
enables users to break the 528 MB per drive barrier, allowing full use of BIOS INT13 CHS information
in drives with a capacity of up to 8.4 GB.
High Speed Host Transfer Rate
The W83759A supports Enhanced IDE PIO mode 3 and Fast ATA PIO mode 3 and 4 timing; jumper
settings or driver programming can be used to select the PIO mode and a 33 or 50 MHz VL-Bus
clock. Different programming timing can be selected for different drives in the same system. The
burst transfer rate is shown in the following table.
IDE COMMAND CYCLE
Dual IDE Channels
Like the W83759, the W83759A supports a secondary IDE address (170h-177h/376h) and IRQ15 for
applications with four hard disk drives. Additionally, the primary and secondary channels can be
independently enabled or disabled by jumper settings or software programming.
Non-disk IDE Peripherals
Because the command cycle can be programmed individually for each drive and dual IDE channels
are supported, non-disk IDE peripherals (such as an ATAPI CD-ROM or tape drive) can be attached
to the secondary IDE without affecting the transfer rate of the ATA disk drive. Sales of ATAPI IDE
CD-ROMs are expected to grow rapidly as these devices become a standard part of many users'
desktop PC setup.
Publication Release Date: May 1995
- 1 - Revision A1