Datasheet

Zeus 2.5-Inch ATA Solid State Drive 17
Primary and Secondary Modes
The Zeus SSD is configured as a high-performance I/O device and supports Primary (Device 0) and
Secondary (Device 1) modes:
I/O Primary and Secondary ATA (IDE) Modes
Primary and secondary drive addressing modes allow hosts to use the ATA-standard’s reserved disk
drive I/O addresses. This provides system designers with the simplest way to accommodate ATA-
protocol devices.
Addressing Modes
Zeus SSDs, on a command-by-command basis, can operate in either CHS or LBA addressing
modes. Identify Drive Information (See Identify Drive Information on page 26.) signals the host
whether the drive supports LBA mode. The host selects LBA mode via the Drive/Head register.
Sector Number, Cylinder Low, Cylinder High, and Drive/Head register bits HS3=0 contain the zero-
based LBA. The sectors are linearly mapped with: LBA = 0 => Cylinder 0, Head 0, Sector 1.
Regardless of the translation mode, a sector LBA address does not change. LBA = (Cylinder * No of
Heads + Head) * (Sectors/Track) + (Sector - 1). Table 6 lists the supported IDE addressing modes.
Table 6. ATA (IDE) Bus Addressing Modes
Device Mode Description
Primary
Drive address at system ATA I/O address 1F0h - 1F7h and 3F6h - 3F7h. The
host must provide chip-enable #CS0 and #CS1. The SSD decodes addresses
DA0 - DA2.
Secondary
Drive address at system ATA I/O address 170h - 177h and 376h - 377h. The
host must provide chip-enable #CS0 and #CS1. The SSD decodes addresses
DA0 - DA2.
#CS0 #CS1 DA2 DA1 DA0 #IORD - “0” #IOWR - “0”
1 1 X X X Hi-Z Not Used
1 0 0 X X Hi-Z Not Used
1 0 1 0 X Hi-Z Not Used
0 0 X X X Invalid Invalid
1 0 1 1 0 Alternate Status Device Control
1 0 1 1 1 Device Address Not Used
0 1 0 0 0 Data Data
0 1 0 0 1 Error Feature
0 1 0 1 0 Sector Count Sector Count
0 1 0 1 1 Sector Number Sector Number
0 1 1 0 0 Cylinder Low Cylinder Low
0 1 1 0 1 Cylinder High Cylinder High
0 1 1 1 0 Drive/Head Drive/Head
0 1 1 1 1 Status Command