LS7566R_08 Datasheet, PDF (5/18 Pages) LSI Computer Systems – 24-BIT x 4-AXES QUADRATURE COUNTER

I/O PINS: The following is a description of the input/output pins.
RSO(Pin 3), RS1 (Pin 2), RS2 (Pin1).
Inputs. These three inputs select the hardware registers for read/write access according to Table 1.
TABLE 1
CS/ RS2 RS1 RS0 RD/ WR/ SELECTED REGISTER OPERATION
1
x
x
x
x
x
none
none
x
x
x
x
0
0
none
none
x
x
x
x
1
1
none
none
0
0
0
0
0
1
[ISR:IMR]
READ (NOTE 2)
0
0
0
1
0
1
MDR0
READ
0
0
1
0
0
1
MDR1
READ
0
0
1
1
0
1
STR
READ
0
1
0
0
0
1
OL0
READ
0
1
0
1
0
1
OL1
READ
0
1
1
0
0
1
OL2
READ
0
1
1
1
0
1
none
none
0
0
0
0
1
0
IMR
WRITE
0
0
0
1
1
0
MDR0
WRITE
0
0
1
0
1
0
MDR1
WRITE
0
0
1
1
1
0
none
none
0
1
0
0
1
0
PR0
WRITE
0
1
0
1
1
0
PR1
WRITE
0
1
1
0
1
0
PR2
WRITE
0
1
1
1
1
0
CMR
WRITE
Note 1. x indicates don’t care case.
Note 2. DB0 through DB3 contain IMR B0 through B3; DB4 through DB7 contain ISR B0 through B3.
CHS0 (Pin 5), CHS1 (Pin 4)
Inputs. These two inputs select one of four axes for read/write access according to the following table. The
registers within the axis are selected according to Table 1.
CHS1
0
0
1
1
TABLE 2
CHS0
0
1
0
1
AXIS
x0
x1
x2
x3
RD/ (Pin 8) Input. A low on RD/ input accesses an ad-
dressed register for read and places the data on the
octal databus, DB<7:0>. The register selection is
made according to Table 1.
CS/ (Pin 9) Input. A low on the CS/ input enables the
chip for read or write operation. When the CS/ input is
high, read and write operations are disabled and the
databus, DB<7:0> is placed in a high impedance
state.
WR/ (Pin 10) Input. A low pulse on the WR/ input
writes the data on the databus, DB<7:0> into the ad-
dressed register according to Table 1. The write op-
eration is completed at the trailing edge of the WR/
pulse.
7566R-121605-5
DB<7:0> (Pin 18 thru Pin 11) Input/Output.
The octal databus DB<7:0> is the input/output portal
for write and read data transfers between LS7566R
and the outside world. During a read operation, when
both CS/ and the RD/ inputs are low, DB<7:0> are
outputs. During a write operation, when both CS/ and
WR/ are low, DB<7:0> are inputs. When CS/ is high,
DB<7:0> are in high impedance state independent of
the states of RD/ and WR/.
PCK (Pin21) Input. A clock applied at PCK input is
used for validating the logic states of the A and B
quadrature clocks and the INDX/ input.
The PCK input frequency, fPCK is divided down by a
factor of 1 or 2 according to bit7 of MDR0. The re-
sultant clock is used to sample the logic levels of the