s-24c128ci-t8t1u3 Seiko Instruments Inc., s-24c128ci-t8t1u3 Datasheet - Page 20

• Manufacturer Part Number: s-24c128ci-t8t1u3
• Description: 2-wire Serial Eeprom S-24c128c 128k-bit
• Manufacturer: Seiko Instruments Inc.

20
2-WIRE CMOS SERIAL E
S-24C128C
Using S-24C128C
1. Adding a pull-up resistor to SDA I/O pin and SCL input pin
2. Equivalent circuit of I/O pin
In consideration of I
The S-24C128C cannot transmit normally without using a pull-up resistor.
In case that the SCL input pin of the S-24C128C is connected to the Nch open drain output pin of the master
device, connect the SCL pin with a pull-up resistor. As well, in case the SCL input pin of the S-24C128C is
connected to the tri-state output pin of the master device, connect the SCL pin with a pull-up resistor in order not to
set it in high impedance. This prevents the S-24C128C from error caused by an uncertain output (high impedance)
from the tri-state pin when resetting the master device during the voltage drop.
The S-24C128C does not have a built-in pull-down or pull-up resistor for the SCL and SDA pins. The WP, A2, A1
and A0 pins have a pull-down resistor. The SDA pin has an open-drain output. The followings are equivalent
circuits of the pins.
SCL
SDA
2
C-bus protocol function, the SDA I/O pins should be connected with a pull-up resistor.
2
PROM
Figure 21 SDA Pin
Seiko Instruments Inc.
Figure 20 SCL Pin
Rev.2.0
_00_H