PT7C43190 Datasheet, PDF (14/32 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
*1. 0 V indicates that there are no potential differences between the VDD pin and VSS pin.
How to Raise the Power Supply Voltage
5. Register Status After Initialization
The status of each register after initialization is as follows.
Real-time data register: 00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S)
Status register 1: "0 B6 B5 B4 0 0 0 0 b"
(In B6, B5, B4, the data of B6, B5, B6 in the status register 1 at initialization is set. Refer to below Figure.)
Status register 2: "00h"
INT1 register: "00h"
INT2 register: "00h"
Clock correction register: "00h"
Free register: "00h"
 Status Register 1 Data at Initialization
6. Low Power Supply Voltage Detection Circuit
The RTC has a low power supply voltage detection circuit, so that users can monitor drops in the power supply voltage by reading
the BLD flag (B1 in the status register 1). There is a hysteresis width of approx. 0.15 V (typ.) between detection voltage and
release voltage (refer to "Characteristics (Typical Data)"). The low power supply voltage detection circuit does the sampling
operation only once in one sec for 15.6 ms. If the power supply voltage decreases to the level of detection voltage (VDET) or less,
"1" is set to the BLD flag so that sampling operation stops. Once "1" is detected in the BLD flag, no sampling operation is
performed even if the power supply voltage increases to the level of release voltage or more, and "1" is held in the BLD flag. If the
BLD flag is "1" even after the power supply voltage is recovered, the internal circuit may be in the indefinite status. In this case,
be sure to initialize the circuit. After reading the BLD flag, the sampling operation is restarted. Without initializing, if the next
BLD flag reading is done after sampling, the BLD flag gets reset to "0". In this case, be sure to initialize although the BLD flag is
in "0" because the internal circuit may be in the indefinite status.
2015-09-0015
PT0274-7 10/16/15
14