AT3550 User Guide V1.00
February 11, 2005
page 9 of 16
OPT1,2: Option Jumpers
configured for normal
operation -- jumpers off
3.2.8 TX/RX CONNECTIONS
The TX and RX connections are for manufacturing use only.
TX/RX: RS232
Communications
GND
GND
RX
TX
3.2.9 EXTERNAL POWER
The XP pins on the Option Header are used to connect external standby power to
the drive. These pins are connected to the Kicker™ Holdup Circuit. Applied
power should be 5 volts +/- 10%. Do not exceed 6 volts on this line, as internal
damage to the drive may result.
The two outside pins on the header are used to connect power to the holdup
circuit. A third pin is needed to connect the grounds of the drive to the power
source.
Jumper Header – J2
XP
XP
GND
GND
GND
3.3 IDE INTERFACE
The AT3550 uses a unitized ATA connector that combines the 40-pin 0.1” IDE
header, the 4-pin AT Power connector, and an 8-pin option jumper header
mounted on the drives controller PCB. Maximum cable length is 18 inches.
Recommended cable length is 12 inches or less, especially if an advanced PIO or
UDMA transfer modes are being used. To achieve full drive performance, a
UDMA cable is required.
