S-24CM01C Datasheet, PDF (20/32 Pages) Seiko Instruments Inc – Write protect function during the low power supply voltage

2-WIRE SERIAL E²PROM
S-24CM01C
Rev.2.0_02_S
 Using S-24CM01C
1. Adding a pull-up resistor to SDA I/O pin and SCL input pin
In consideration of I²C-bus protocol function, the SDA I/O pins should be connected with a pull-up resistor.
The S-24CM01C cannot transmit normally without using a pull-up resistor.
In case that the SCL input pin of the S-24CM01C 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-24CM01C 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-24CM01C from error caused by an uncertain output (high impedance) from the
tri-state pin when resetting the master device during the voltage drop.
2. Equivalent circuit of input and I/O pin
The S-24CM01C does not have a built-in pull-down or pull-up resistor for the SCL and SDA pins. The WP, A2, and
A1 pins have a pull-down resistor. The SDA pin has an open-drain output. The following are equivalent circuits of the
pins.
SCL
SDA
Figure 19 SCL Pin
Figure 20 SDA Pin
20