Study Notes

To understand 100Mb/s throughout. Servial factors must be consided. With a 16-bit data bus, two byte are transmitted per bus transation. Thus to achieve a throughout of 100Mbytes/s, the data bus must be clocked at 50MHz. To minimize strobe design complexity, Ultra ATA uses a “double data rate” or double-edge clocking mechanism for all Ultra DMA transfers. Using this technology, data is registed both on the rising and falling edges of the data strobe, halving the required strobe frequency. Thus the bandwidth is:

25 MHz strobe
x 2 for double data rate clocking
x 16 bit per edge
/ 8 bits per byte
——————————–
=100 Mbytes/sec

ESD:electrostatic discharge
Shipping package, ESD protecting bag are responsibility for the users.

Controll electionics:
The driver is electronically controlled by a microprocessor, several logic modules, digital/analog modules, and various drivers and receivers. The controll electronics preforms the following major function:
1. Controls and interpres all interface signals between the host controller and driver.
2. Controls read write accessing of the disk media, including defect management and error recovery.
3. Controls staring, stopping and monitoring of the spindle.
4. Conducts a power-up sequence and calibrates the serio.
5. Analyze servo signals to provide closed loop control. These include position erre signal and estimated velocity.
6. Monitors the actuator position and determines the target track for a seek operation
7. Controls the voice coil driver to align the actuator in a desired position
8. Constantly monitors error conditions of the servo and takes corresponding action if an error occurs
9. Monitors various timers such as head settle and servo failure.
10.Perform self-checkout(diagnostics)

Actuator: The read/write heads are mounted in the actuator. The actuator is a swing-arm assembly driven by a voice coild motor. A closed-loop positioning servo controls the environment of the actuator. An embedded servo patterm supplied feedback to the positioning servo to keep the read/write heads centered over the desired track.

The actuator assembly is balanced to allow vertical or horizontal mounting without adjustment. When the driver is powered off, the actuator automatically moves the head to the actuator ramp outside of the disk where it parks.

Key: Pin position 20 has no connection pin, it is recommended to close the respective position of the cable connector in order to avoid incorrect insertion.