Signal Summary; Signal Descriptions - Samsung WA31273A Technical Manual

AT INTERFACE and ATA COMMANDS
6-2-2

Signal Summary

The physical interface consists of single ended TTL compatible receivers and drivers
communicating through a 40-conductor flat ribbon non-shielded cable using an
asynchronous interface protocol. The pin numbers and signal names are shown in Table
6-1. Reserved signals are be left unconnected. 6-2-3 Signal Descriptions
6-2-3

Signal Descriptions

The interface signals and pins are described below in more detail than shown in Table 6-
1. The signals are listed according to function, rather than in numerical connector pin
order.
6-2-3-1 CS1FX- (Drive Chip Select 0)
This is the chip select signal decoded from the host address bus used to select the
Command Block Registers.
6-2-3-2 CS3FX- (Drive Chip Select 1)
This is the chip select signal decoded from the host address bus used to select the
Control Block Registers.
6-2-3-3 DA0-2 (Drive Address Bus)
This is the 3-bit binary coded address asserted by the host to access a register or data
port in the drive.
6-2-3-4 DASP- (Drive Active/Slave Present)
This is a time-multiplexed signal that indicates that a drive is active, or that Drive 1 is
present. This signal is an open collector output and each drive has a 10K ohm pull-up
resistor on this signal.
During power on initialization or after RESET- is negated, DASP- is asserted by Drive 1
within 400 msec to indicate that Drive 1 is present. Drive 0 allows up to 450 msec for
Drive 1 to assert DASP-. If Drive 1 is not present, Drive 0 may assert DASP- to drive an
activity LED. DASP- is negated following acceptance of the first valid command by
Drive 1 or after 31 seconds, whichever comes first. Any time after negation of DASP-,
either drive may assert DASP- to indicate that a drive is active.
6-2-3-5 DD0-DD15 (Drive Data Bus)
This is an 8- or 16-bit bi-directional data bus between the host and the drive. The lower 8
bits are used for 8-bit transfers e.g. registers, ECC bytes.
6-
2 WA31273A / WA32543A / WA33203A / WA3216A / WA31083A / WA32162A