ST62T15CM6 STMicroelectronics, ST62T15CM6 Datasheet - Page 21

• Manufacturer Part Number: ST62T15CM6
• Description: 8BIT MCU OTP 2K, SMD, 62T15, SOIC20
• Manufacturer: STMicroelectronics

Specifications of ST62T15CM6

• Controller Family/series: ST6
• Core Size: 8bit
• No. Of I/o's: 20
• Program Memory Size: 2KB
• Ram Memory Size: 64Byte
• Cpu Speed: 8MHz
• Oscillator Type: External Only
• No. Of Timers: 1
• Digital Ic Case: RoHS Compliant
• Peripherals: ADC,
• Rohs Compliant: No
• Processor Series: ST62T1x
• Core: ST6
• Data Bus Width: 8 bit
• Program Memory Type: EPROM
• Data Ram Size: 64 B
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 20
• Number Of Timers: 2
• Operating Supply Voltage: 3 V to 6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOP-28
• Development Tools By Supplier: ST62GP-EMU2, ST62E2XC-EPB/110, ST62E6XC-EPB/US, STREALIZER-II
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / Rohs Status: In Transition

CLOCK SYSTEM (Cont’d)
5.1.2 Oscillator Safeguard (OSG)
The Oscillator Safeguard (OSG) feature is a
means of dramatically improving the operational
integrity of the MCU. It is available when the OSG
ENABLED option is selected in the option byte (re-
fer to the Option Bytes section of this document).
The OSG acts as a filter whose cross-over fre-
quency is device dependent and provides three
basic functions:
– Filtering spikes on the oscillator lines which
– Management of the Low Frequency Auxiliary
– Automatically limiting the f
5.1.2.1 Spike Filtering
Spikes on the oscillator lines result in an effectively
increased internal clock frequency. In the absence
of an OSG circuit, this may lead to an over fre-
quency for a given power supply voltage. The
OSG filters out such spikes (as illustrated in
10). In all cases, when the OSG is active, the max-
Figure 10. OSG Filtering Function
Figure 11. LFAO Oscillator Function
would result in driving the CPU at excessive fre-
quencies
Oscillator (LFAO), (useable as low cost internal
clock source, backup clock in case of main oscil-
lator failure or for low power consumption)
a function of supply voltage, to ensure correct
operation even if the power supply drops.
f
f
f
OSC
LFAO
INT
f
f
f
OSC
OSG
INT
MAIN OSCILLATOR
STOPS
INT
clock frequency as
f
OSC>
f
OSG
INTERNAL CLOCK DRIVEN BY LFAO
Figure
imum internal clock frequency, f
f
5.1.2.2
Variations
Over-frequency, at a given power supply level, is
seen by the OSG as spikes; it therefore filters out
some cycles in order that the internal clock fre-
quency of the device is kept within the range the
particular device can stand (depending on V
and below f
cy with OSG enabled.
5.1.2.3 LFAO Management
When the OSG is enabled, the Low Frequency
Auxiliary Oscillator can be used (see
5.1.3).
Note: The OSG should be used wherever possible
as it provides maximum security for the applica-
tion. It should be noted however, that it can in-
crease power consumption and reduce the maxi-
mum operating frequency to f
Characteristics section).
Caution: Care has to be taken when using the
OSG, as the internal frequency is defined between
a minimum and a maximum value and may vary
depending on both V
cise timing measurements, it is not recommended
to use the OSG.
OSG
, which is supply voltage dependent.
RESTARTS
MAIN OSCILLATOR
Management
OSG
: the maximum authorised frequen-
DD
f
OSC<
and temperature. For pre-
f
OSG
of
ST6215C/ST6225C
OSG
Supply
INT
(see Electrical
, is limited to
Voltage
Section
21/105
DD
),
1