S-7750C Datasheet, PDF (26/44 Pages) Seiko Instruments Inc – PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E2PROM CIRCUIT)

PROGRAMMABLE PORT CONTROLLER (PORT EXPANDER WITH BUILT-IN E²PROM CIRCUIT)
S-7750C
Rev.1.1_00
3. Acknowledgment check
The I²C-bus protocol includes an acknowledgment check function as a handshake function to prevent a
communication error. This function allows detection of a communication failure during data communication between
the master device and the S-7750C.
4. Power-on-clear circuit
The S-7750C has a power-on-clear circuit that initializes itself at the same time during power-on. Unsuccessful
initialization may cause a malfunction. To operate the power-on-clear circuit normally, the following conditions must be
satisfied to raise the power supply voltage.
4. 1 Raising power supply voltage
As shown in Figure 32, raise the power supply voltage from 0.2 V max., within the time defined as t_RISE which is the
time required to reach the power supply voltage to be set.
For example, if the power supply voltage is 3.0 V, t_RISE = 100 ms as seen in Figure 33. The power supply voltage
must be raised within 100 ms.
t_RISE (Max.)
Power supply voltage (V_CCH)
V_INIT (Max.) 0.2 V
0 V^*1
t_INIT^*2 (Max.)
*1. 0 V means there is no difference in potential between the VCCH pin and the VSS
pin of the S-7750C.
*2. t_INIT is the time required to initialize the S-7750C. No instructions are accepted
during this time.
Figure 32 Raising Power Supply Voltage
26
Seiko Instruments Inc.