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How to calculate ADC sampling time for stm32f205?
From RM ( Reference Manual RM0033 for STM32F205) you know that total conversion time is equal to 12ADC clocks + your sampling time. For example if the ADC clock is 12MHz and the sampling time is 84 clock cycles then total conversion time will be 84 + 12 ADC cycles = 8us, and max ADC sample speed = 1/8us = 125kSPS.
How to calculate the ADC Clock sampling time?
Use the prescalar as 4. This is bring the ADC CLOCK to 12.5 MHz Use the Sampling Time of 112 CYCLES. Now conversion Time = (112 + 12) / 12.5 MHz = 9.9 us The above example is just one of the combinations of many, that you can do for the same conversion time.
How to convert adcclk sampling time to tconv?
The total conversion time is calculated as follows: Tconv = Sampling time + 12.5 cycles Example: With an ADCCLK = 14 MHz and a sampling time of 1.5 cycles: Tconv = 1.5 + 12.5 = 14 cycles = 1 μs To set “particular” sample time you can use external trigger conversion with timer update event as trigger.
How is a conversion triggered in STM32 ADC?
Conversion can be triggered by an external event (e.g. timer capture, EXTI line). If the EXTTRIG control bit is set then external events are able to trigger a conversion.
How does sampling time affect ADC sample rate?
The longer the sampling time, the slower the ADC sample rate will be. On some STM micros you can use built-in opamps as the input buffers. You can also have the external ones to make readings quicker and more precise. From RM ( Reference Manual RM0033 for STM32F205) you know that total conversion time is equal to 12ADC clocks + your sampling time.
How to calculate ADC sampling time and rate?
For example if the ADC clock is 12MHz and the sampling time is 84 clock cycles then total conversion time will be 84 + 12 ADC cycles = 8us, and max ADC sample speed = 1/8us = 125kSPS. I’ll let you work out the details for your particular case, but I’d like to add some more clarity.
How is the sampling time of a channel calculated?
Each channel can be sampled with a different sample time. The total conversion time is calculated as follows: Tconv = Sampling time + 12.5 cycles Example: With an ADCCLK = 14 MHz and a sampling time of 1.5 cycles: Tconv = 1.5 + 12.5 = 14 cycles = 1 μs