V3021SO8A EMMICRO [EM Microelectronic - MARIN SA], V3021SO8A Datasheet - Page 12

• Manufacturer Part Number: V3021SO8A
• Description: Ultra Low Power 1-Bit 32 kHz RTC
• Manufacturer: EMMICRO [EM Microelectronic - MARIN SA]

Test Modes
An external signal generator can be used to drive the
divider chain of the V3021. Fig. 11a and 11b show how to
connect the signal generator.
increased by increasing the signal generator frequency to
a maximum of 128 kHz. An external signal generator and
test modes can be combined.
To leave test both test bits (address 0, bits 2 and 3) must
be cleared by software. Test corrupts the current time
and date and so the time and date should be reloaded
after a test session.
Signal Generator Connection
Note: The peak value of the signal provided by the signal
generator should not exceed 2 V on XO.
Note: The peak value of the signal provided by the signal
generator should not exceed 2 V on XO.
Copyright © 2005, EM Microelectronic-Marin SA
Addr. 0
bit 3
0
0
1
1
Addr. 0
bit 2
R
0
1
0
1
Function
Normal operation
All time keeping accelerated by 32
Parallel increment of all time data
at 1 Hz with no carry over
Parallel increment of all time data
at 32 Hz with no carry over
The speed can be
Fig. 11b
Fig. 11a
Table 8
Crystal Layout
In order to ensure proper oscillator operation we
recommend the following standard practices:
- Keep traces as short as possible
- Use a guard ring around the crystal
Fig. 12 shows the recommended layout.
Oscillator Layout
Access Considerations
The section "Communication Cycles" describes the serial
data sequences necessary to complete a communication
cycle. In common with all serial peripherals, the serial
data sequences are not re-entrant, thus a high priority
interrupt, or another software task, should not attempt to
access the V3021 if it is already in the middle of a cycle.
A semaphore (software flag) on access would allow the
V3021 to be shared with other software tasks or interrupt
routines.
communication cycle and thus interrupt routines (which do
not use the V3021) can be fully executed in mid cycles
without any consequences for the V3021.
12
There is no time limit on the duration of a
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V3021
Fig. 12