Filter
Top Products
8155/8156/8155-2/8156-2
DESCRIPTION
The
8155/8156
contains the following:
•
2k
Bit Static RAM organized
as
256 x 8
•
Tw08-bit
1/0 ports (PA &
PB)
andone6-bit
110
port (PC)
• .14-bit timer-counter .
The
101M
(IO/Memory Select) pin selects either the five
registers (Command.
Status.
PAo-7.
PBO-7.
PCO-5)
or
the memory (RAM). portion.
(See
Figure 1.)
The 8-bit address
on
the AddresslData lines. Chip Enable
input CE
or
CEo
and
101M
are all latched on-chip at the
falling edge of ALE.
(See Figure 2.)
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
L
____
_
_________
..J
Figure
1.
8155/8156 Internal Registers
C'E
181551
\
OR
CE
181561
I
101M
\
A°0-7
X
ADDRESS
ALE
RDORWR
/
\
/
I
I\.
/
V
I\.
X
DATA
VALID
NOTE:
FOR
OETAILEO TIMING INFORMATION,
SEE
FIGURE 12 ANO A.C. CHARACTERISTICS.
Figure
2.
8155/8156 On-Board Memory Read/Wrlte Cycle
6-84
\
/
\