Page 89 - ARM Based Microcontroller Projects Using MBED

6.4 EXERCISES 75
6.2.11 SPI Interface
Five SPI interfaces in slave and master modes are supported. Three SPI interfaces can op-
erate at up to 50Mbit/s while the remaining two can communicate at up to 25Mbit/s.

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6.2.12 I S Interface
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Five standard I S interfaces are supported which can operate in master or slave modes, in
simplex or full duplex communication modes. Audio sampling frequencies from 8 to 192kHz
are supported.

6.2.13 USART
Three USARTs are supported by the microcontroller. Two of the USARTs can communi-
cate at up to 12.5Mbit/s, the remaining one can communicate at up to 6.25Mbit/s.

6.3 SUMMARY

In this chapter, we have learned about the following:
• Key features of the STM32F411RET6 microcontroller
• Power modes
• Electrical characteristics
• ADC and DAC
• Interrupt controller
• Timers
• Clock circuit
• Temperature sensor
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•I C, SPI, and I S interfaces
• GPIO ports

6.4 EXERCISES

1. Describe the various power modes of the STM32F411RET6 microcontroller.
2. What is the maximum current that can be drawn from a GPIO pin?
3. What is the total maximum current that can be drawn from all the GPIO pins?
4. Describe how we can drive loads requiring more than 20mA.
5. Explain the various clock sources available on the STM32F411RET6 microcontroller.
6. Explain the difference between push-pull and open-drain output.
7. Explain the difference between pull-up and pull-down pin.
8. What do you understand if a GPIO pin is +5V tolerant?