PRELIMINARY/CONFIDENTIAL
12
MACH2 2.5-Inch Serial ATA Solid State Drive
I
NTERFACE
S
PECIFICATIONS
SSD Operation
The SSD is comprised of the following primary functional blocks: the SATA interface connector,
controller and NAND flash memory. Read/write data transfer requests are initiated by the host via the
SATA bus interface. Once received, the controller, under the direction of the microcontroller,
processes the request.
Commands that do not require data to be read from or written to the flash memory controller are
typically handled by the controller. Some commands may require the controller to use external
circuitry that do not involve the flash memory controller.
Write Operations
When a write operation is requested and data is received, the controller uses integrated DMA
controllers to transfer the data from host memory to the flash memory controller. Through a standard
ATA (IDE) interface, the flash memory controller transfers the data from the controller to available
locations in the local flash memory of the SSD. The controller notifies the host after the write
operation is completed.
Read Requests
If a read request is received, the controller retrieves the data from the local flash memory via the flash
memory controller. If the controller is responding to a PIO read operation, it presents the data to the
ATA bus. If it is responding to a UDMA read request, the controller writes the data directly to the
system memory on the host. Regardless of the type of operation (PIO or UDMA), the controller
notifies the host when the data is ready for transmission.
The microcontroller is responsible for initiating and controlling all
activity within the controller, including bad block mapping and
executing the wear-leveling algorithms.
The controller decodes an incoming host command, and will
configure the appropriate interrupts and status for the local
microprocessor to handle various ATA commands. For read and
write transfer commands, the hardware can handle the initial
handshake with the host automatically. If firmware enables full auto
mode, read and write transfers can be fully handled by hardware
with minimum firmware support.
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