STR91XFAX32 Datasheet, PDF (35/99 Pages) STMicroelectronics – ARM966E-S™ 16/32-Bit Flash MCU with Ethernet, USB, CAN, AC motor control, 4 timers, ADC, RTC, DMA

STR91xFAx32 STR91xFAx42 STR91xFAx44
Functional overview
3.24
3.24.1
A/D converter (ADC) with DMA
The STR91xFA provides an eight-channel, 10-bit successive approximation analog-to-
digital converter. The ADC input pins are multiplexed with other functions on Port 4 as
shown in Table 9. Following are the major ADC features:
● Fast conversion time, as low as 0.7 usec
● Accuracy. Integral and differential non-linearity are typically within 4 conversion counts.
● 0 to 3.6V input range. External reference voltage input pin (AVREF) available on 128-
pin packages for better accuracy on low-voltage inputs. See Table 12: Operating
conditions, for restrictions to the relative voltage levels of VDDQ, AVDD, AVREF, and
AVREF_AVDD.
● CPU Firmware may convert one ADC input channel at a time, or it has the option to set
the ADC to automatically scan and convert all eight ADC input channels sequentially
before signalling an end-of-conversion
● Automatic continuous conversion mode is available for any number of designated ADC
input channels
● Analog watchdog mode provides automatic monitoring of any ADC input, comparing it
against two programmable voltage threshold values. The ADC unit will set a flag or it
will interrupt the CPU if the input voltage rises above the higher threshold, or drops
below the lower threshold.
● The ADC unit goes to stand-by mode (very low-current consumption) after any reset
event. CPU firmware may also command the ADC unit to stand-by mode at any time.
● ADC conversion can be started or triggered by software command as well as triggers
from Timer/Counter (TIM), Motor Controller and input from external pin.
DMA
A programmable DMA channel may be assigned by CPU firmware to service each ADC
conversion result for fast DMA single-transfer.
3.25
Standard timers (TIM) with DMA
The STR91xFA has four independent, free-running 16-bit timer/counter modules designated
TIM0, TIM1, TIM2, and TIM3. Each general purpose timer/counter can be configured by
firmware for a variety of tasks including; pulse width and frequency measurement (input
capture), generation of waveforms (output compare and PWM), event counting, delay
timing, and up/down counting.
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