Transcript analog clock

Microcontroller based system
design
Asst. Prof. Dr. Alper ŞİŞMAN
ADC Features
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3 ADCs : ADC1 (master), ADC2 and ADC3 (slaves)
Maximum frequency of the ADC analog clock is 36MHz.
12-bits, 10-bits, 8-bits or 6-bits configurable resolution.
ADC conversion rate with 12 bit resolution is up to:
– 2.4 M.sample/s in single ADC mode,
– 4.5 M.sample/s in dual interleaved ADC mode,
– 7.2 M.sample/s in triple interleaved ADC mode.
• Conversion range: 0 to 3.6 V.
• ADC supply requirement: VDDA = 2.4V to 3.6V at full speed
and down to 1.65V at lower speed.
• Up to 24 external channels.
• 3 ADC1 internal channels connected to:
– Temperature sensor,
– Internal voltage reference : VREFINT (1.2V typ),
– VBAT for internal battery monitoring.
• External trigger option for both regular and injected
conversion.
• Single and continuous conversion modes.
• Scan mode for automatic conversion of channel 0 to
channel ‘n’.
• Left or right data alignment with in-built data coherency.
• Channel by channel programmable sampling time.
• Discontinuous mode.
• Dual/Triple mode (with ADC1 and ADC2 or all 3 ADCs).
• DMA capability
• Analog Watchdog on high and low thresholds.
• Interrupt generation on: End of Conversion &End of
Injected conversion
• Analog watchdog
• Overrun
ADC Speed
Conversion Time
• ADCCLK, up to 36MHz, taken from PCLK through a prescaler
(Div2, Div4, Div6 and Div8).
• Programmable sample time for each channel (from 4 to 480
clock cycles)
• Total conversion Time = TSampling + Tconversion
• With Sample time= 3 cycles @ ADC_CLK = 36MHz 
conversion time is :
total
Analog Watchdog
• 12-bit programmable analog watchdog low and high
thresholds
• Enabled on one or all converted channels: one regular
or/and injected channel, all injected or/and regular
channels.
• Interrupt generation on low or high thresholds
detection
ADC Modes
Single Channel, single conversion Mode:
• This is the simplest ADC mode. In this mode, the ADC
performs the single conversion (single sample) of a single
channel x and stops after completion of the conversion.
• This mode can be used for the measurement of a voltage level
to decide if the system can be started or not. Measure the
voltage level of the battery before starting the system: if the
battery has a low level, the “low battery” message appears. In
this case, do not start the system.
MultiChannel (Scan), single conversion Mode:
• This mode is used to convert some channels
successively in independent mode. With the ADC
sequencer, you can use this ADC mode to configure
any sequence of up to 16 channels successively with
different sampling times and in different orders. You
can for example carry out the sequence shown in the
following Figure. In this way, you do not have to stop
the ADC during the conversion process in order to
reconfigure the next channel with a different
sampling time. This mode saves additional CPU load
and heavy software development.
• This mode can be used to make single measurements of
multiple signal levels (voltage, pressure, temperature, etc.)
to decide if the system can be started or not in order to
protect the people and equipment.
• It can likewise be used to convert signals coming from
strain gauges to determine the directions and values of the
different strains and deformations of an object.
• Single Channel Continuous Conversion Mode:
The single-channel continuous conversion mode converts a
single channel continuously and indefinitely in regular channel
conversion. The ADC converts the channels continuously
without any intervention from the CPU. Additionally, the DMA
can be used in circular mode, thus reducing the CPU load.
• Regulation of an oven temperature, etc.In the case of the
oven temperature regulation, the temperature is read and
compared to the temperature set by the user.
• Multichannel Continious conversion mode
The multichannel, or scan, continuous mode can be used
to convert some channels successively with the ADC in
independent mode. With the sequencer, you can
configure any sequence of up to 16 channels successively
with different sampling times and different orders.
• İnjected Conversion Mode:
This mode is intended for use when conversion is
triggered by an external event or by software.
The injected group has priority over the regular channel
group. It interrupts the conversion of the current channel
in the regular channel group.
ADC Dual Mode
• ADCs: ADC1 master and ADC2 slave, ADC3 is
independently.
• The start of conversion is triggered alternately or
simultaneously by the ADC1 master to the ADC2 slave
depending on the mode selected.
• 6 ADC dual modes
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Dual
Simultaneous
Mode
The dual regular simultaneous ADC mode is used to perform
two conversions simultaneously owing to the synchronization
of ADC1 and ADC2.
• Each ADC converts a channel sequence (with scan enabled
and the sequencer of each ADC configured) or converts a
single channel (scan disabled). The conversion can be started
with an external trigger or by software. In this mode, the
conversion results of ADC1 and ADC2 are stored in ADC1’s
data register (32-bit format)
• The dual regular simultaneous mode can be used in
applications where two signals should be sampled and
converted at the same time
Dual Interleaved Mode
ADC Triple Mode
• ADCs: ADC1 master, ADC2 and ADC3 slaves.
• The start of conversion is triggered alternately or
simultaneously by the ADC1 master to the ADC2
and ADC3 slaves depending on the mode
selected.
• 6 ADC Triple modes.