mx878 Clare, Inc., mx878 Datasheet - Page 6

• Manufacturer Part Number: mx878
• Description: 8-channel, 60v Relay/load Driver Open Drain Output, 3 Wire Interface
• Manufacturer: Clare, Inc.

MX878
with 8-bit input control. The MX878 interfaces to a
microprocessor through a standard 3 wire serial
interface and an active low chip select, or can be
used in a parallel-in, parallel-out configuration.
the MX878 through the parallel input pins, IN0
through IN7 on the falling edge of the chip select
pin, CS . When CS is in a logic low state, serial
data can be transferred to the I/O register through
the serial input pin, SDI, and from the I/O register
through the serial output pin, SDO. Parallel or
serial input data is transferred from the I/O
register to the latch and high voltage output
drivers, OUT0 through OUT7, on the positive
edge of CS . This data remains latched until the
next positive edge of CS .
serial clock pin, SCK. Serial data presented at the
SDI pin is transferred to the shift register on the
positive edge of SCK. Data shifts out of the
register through the SDO pin on the negative
edge of SCK. SDI and SCK are ignored, and
SDO transitions to a high impedance condition
when CS is at a logic high state.
the SDI pin. This data is accepted on the rising
edge of SCK. A specific output is programmed to
a logic high state if SDI is at a logic high state
during the rising edge of SCK. Conversely, a
specific output is programmed to a logic low state
if SDI is at a logic low state during the rising edge
of SCK. Outputs transition to their programmed
states on the positive edge of CS if the output
enable pin, OE is in a logic high state.
serial output pin, SDO on the falling edge of CS .
Input data from IN6 through IN0 is sequentially
presented at SDO on negative SCK transitions if
CS remains in a logic low state. If CS is at a
logic low state beyond 8 cycles of SCK, SDI data
that has propagated through the I/O register will
then be presented at SDO. The SDO pin
transitions to a high impedance state when CS
is in a logic level high state, thus allowing multiple
serial peripherals to share the microprocessor
data pin.
Functional Description
MX878
Drawing No. 087809
The MX878 is an 8 channel high voltage driver
Parallel data is transferred to the I/O register of
The 8-bit I/O shift register is clocked by the
The MSB input data (IN7) is presented at the
Serial data is received by the MX878 through
6
outputs OUT0 through OUT7 when logic high. A
logic low level on OE forces the OUT0 through
OUT7 outputs to a high impedance state.
connecting SDO to SDI of the next device. Pins
SCK and CS are common to all devices in serial
cascade. For n-cascaded devices the CS should
remain low for 8n cycles of SCK.
parallel-out level shifter and driver. SCK must
remain at a logic low state when operating in this
mode. Parallel input data presented to IN0
through IN7 is captured on the falling edge of
CS . This data is transferred to OUT0 through
OUT7 on the rising edge of CS , and remains
latched until the next rising edge of CS .
An output enable pin, OE enables the driver
Devices
The MX878 can also operate as a parallel-in,
SCK
SDO
CS
OUT7
OUT6
OUT5
OUT4
OUT3
OUT2
OUT1
OUT0
IN4
IN3
IN2
IN1
IN0
SDI
IN7
IN6
IN5
*
0
0
1
0
1
1
1
0
Serial Data Transfer Example
t1
1
0
may
0
0
be
0
1
0
0
serially
0
1
www.claremicronix.com
1
1
cascaded
1
1
0
0
06/08/06
SDI at
time t1
1
0
0
0
1
1
0
0
by