LSI 53C875A Manual De Usuario
Signal Descriptions
3-3
3.2 Signal Descriptions
The Signal Descriptions are divided into
,
,
, and
.
The PCI Bus Interface Signals are subdivided into
,
,
,
,
, and
.
The SCSI Bus Interface Signals are subdivided into
, and
.
Signals are assigned a type. There are five signal types:
3.2.1 Internal Pull-ups on LSI53C875A Signals
Several signals in the LSI53C875A have internal pull-up resistors.
describes the conditions that enable these pull-ups.
I
Input, a standard input only signal.
O
Output, a standard output driver (typically a Totem Pole Output).
I/O
Input and output (bidirectional).
T/S
3-state, a bidirectional, 3-state input/output signal.
S/T/S
Sustained 3-state, an active LOW 3-state signal owned and driven by
one and only one agent at a time.
one and only one agent at a time.
Table 3.1
LSI53C875A Internal Pull-ups
Signal Name
Pull-up Current Conditions for Pull-up
IRQ/
25
µ
A
Pull-up enabled when the IRQ mode bit (bit 3 of DCNTL
(0x3B)) is cleared.
(0x3B)) is cleared.
GPIO[1:0]
25
µ
A
Pull-up enabled when bits [1:0] of
are not set.
TEST_HSC/
25
µ
A
Pull-up enabled all the time.
TEST_RST/
25
µ
A
Pull-up enabled all the time.
TRST, TCK, TMS, TDI
25
µ
A
Pull-up enabled all the time.