...
Analog-to-digital conversion of the different channels can be performed both single mode, in which the ADC converts all the channels at once in a single sequence of conversions, and continuous mode, where the device automatically restarts the scan after converting all of the different channels. The 12-bit value obtained from the conversion will be stored in the ADC read-only data register (ADC_DR).
Driver Inputs
SMT32F0 Interrupts
Interrupts on the SMT32 are managed by the extended interrupts and events controller (EXTI), which allows for the management of up to 32 different interrupt lines (23 external and 9 internal). Each line can have both its active edge and interrupt priority programmed independently.
In order to generate an interrupt for an external line, the line must be configured. To do this, the bit in the interrupt mask register (EXTI_IMR) corresponding to the interrupt line must be set to '1', along with the corresponding bits in the desired edge trigger registers (Should an interrupt be triggered on a high-to-low or low-to-high change?), which are EXTI_RTSR and EXTI_FTSR for rising and falling edges respectively. Once this is done, an interrupt request will be generated once the selected edge appears on the external interrupt line and the pending bit corresponding to said interrupt line will be set. The STM32 will clear this bit automatically once the ISR concludes.
The STM32 has the first 16 external interrupt lines set aside for the GPIOs, meaning that there are only 16 digital interrupts available for use on the STM32. The GPIOs are mapped to the external interrupt lines as follows:
This means that only one port can have have an interrupt enabled for a given pin number at a time. For instance, enabling interrupt on PA0 will preclude the enabling of interrupts for pin 0 of any other port.
Handling input requests
The driver control inputs will be connected to onboard GPIOs. As we are only concerned with handling each input as they are triggered, most of the inputs will be set to be handled through the use of interrupts (for the prototype, we will collect information on the gas pedal through polling). all set to be handled by interrupt service routine.