24LC41
8.0
8.1
PIN DESCRIPTIONS
DSDA
8.4
MSCL
This pin is used to transfer addresses and data into and
out of the DDC Monitor Port, when the device is in the
bi-directional Mode. In the Transmit-Only Mode, which
only allows data to be read from the device, data is also
transferred on the DSDA pin. This pin is an open drain
terminal, therefore the DSDA bus requires a pullup
resistor to V
CC
(typical 10K鈩?for 100 kHz, 1K鈩?for 400
kHz).
For normal data transfer in the bi-directional Mode,
DSDA is allowed to change only during DSCL or MSDA
low. Changes during DSCL high are reserved for indi-
cating the START and STOP conditions.
This pin is the clock input for the Microcontroller Access
Port, and is used to synchronize data transfer to and
from the device.
8.5
MSDA
This pin is used to transfer addresses and data into and
out of the Microcontroller Access Port. This pin is an
open drain terminal, therefore the MSDA bus requires
a pullup resistor to V
CC
(typical 10K鈩?for 100 kHz, 1K鈩?/div>
for 400 kHz).
MSDA is allowed to change only during MSCL low.
Changes during MSCL high are reserved for indicating
the START and STOP conditions.
8.2
DSCL
8.6
MWP
This pin is the clock input for the DDC Monitor Port
while in the bi-directional Mode, and is used to synchro-
nize data transfer to and from the device. It is also used
as the signaling input to switch the device from the
Transmit-Only Mode to the bi-directional Mode. It must
remain high for the chip to continue operation in the
Transmit-Only Mode.
This pin is used to write protect the 4K memory array
for the Microcontroller Access Port.
This pin must be connected to either V
SS
or V
CC
.
If tied to Vss, normal memory operation is enabled
(read/write the entire memory).
If tied to V
CC
, WRITE operations are inhibited. The
entire memory will be write-protected. Read operations
are not affected.
8.3
VCLK/DWP
This pin is the clock input for the DDC Monitor Port
while in the Transmit-Only Mode. In the Transmit-Only
Mode, each bit is clocked out on the rising edge of this
signal. In the bi-directional Mode, a high logic level is
required on this pin to enable write capability.
漏
1996 Microchip Technology Inc.
DS21140B-page 11
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