rs5c62 RICOH Co.,Ltd., rs5c62 Datasheet - Page 42

• Manufacturer Part Number: rs5c62
• Description: Real-time Clock
• Manufacturer: RICOH Co.,Ltd.

38
RP/RF/RS5C62
Category
Answer 5: As in Answer 4 above, this phenomenon may occur when an alarm interrupt and a cyclic inter-
Answer 6: Time or alarm digits which are non-existent or indicated in non-BCD notation can be set in the
Answer 7: An alarm interrupt is normally output from the INTR pin in battery backup (while the CE pin is
Answer 8: The RP/RF/RS5C62 are configured to issue a daily alarm and cannot be reconfigured to gener-
Note
Question 5 : An attempt to disable a cyclic interrupt by setting the CTFG bit to “0” in the control regis-
ter 2 results in holding the INTR pin output low. What is the cause of this phenomenon?
Question 6 : What will happen if non-existent time is set?
Question 7 : How can an alarm interrupt be used in battery backup? (Why is an alarm interrupt not out-
put in battery backup?)
Question 8 : How can an alarm interrupt be output on a monthly basis?
: The RP/RF/RS5C62 are designed to reduce current consumption (ensure typical current con-
rupt are simultaneously output from the INTR pin.
time counter or the alarm register without causing any trouble. If such invalid digits are left,
however, they may cause faulty time count operation in case of a carry or mismatching between
clock time and alarm time.
held low). Its output is most likely to fail, therefore, when the other end of the pull-up resistor
of the INTR pin is connected to any power supply which may be turned off. To prevent this
problem, confirm that the other end of the pull-up resistor of the INTR pin is connected to the
backup battery.
ate an alarm interrupt on a monthly basis. Considering that they are designed to reduce cur-
rent consumption as described in “Note” below, an advisable alternative action is to generate an
alarm interrupt to the CPU on a daily basis and keep track of alarm dates in a software-con-
trolled process.
sumption on the order of 1µA for 3V). Daily current consumption can be calculated as follows :
Assuming, for example, that an alarm interrupt to the CPU is generated on a daily basis as the
CPU is operating for a period of 0.5seconds with peak current consumption of 20mA, daily cur-
rent consumption can be calculated from the equation : 0.5s´20mA /60´60´24 = 0.115µA. This
means a total base current of a little more than 1µA, a slight increase in current consumption.
Questions and Answers