The Apollo3 module has many hardware peripherals capable of generating software interrupts. In order to use these, a special function naming system is used to call the various ISRs (Interrupt Service Routines).
For more information on how and when each peripheral-specific interrupt is called, have a look at the Apollo3 datasheet and the examples in the Ambiq SDK.
Note: this does not include hardware interrupts. To use those, look at the interrupts example here and the official Arduino reference here.
The Apollo3 microcontroller's interrupts are mapped through the NVIC (Nested Vectored Interrupt Controller). See section 3.1 of the datasheet for more details. The following is a table of the specific peripheral interrupt, its IRQ number, and its ISR name.
| Peripheral Name | IRQ Number | ISR Name |
|---|---|---|
| Brownout | 0 | am_brownout_isr |
| Watchdog | 1 | am_watchdog_isr |
| RTC | 2 | am_rtc_isr |
| Voltage Comparator | 3 | am_vcomp_isr |
| I2C/SPI Slave | 4 | am_ioslave_ios_isr |
| I2C/SPI Slave Register Address | 5 | am_ioslave_acc_isr |
| I2C/SPI Master 0 | 6 | am_iomaster0_isr |
| I2C/SPI Master 1 | 7 | am_iomaster1_isr |
| I2C/SPI Master 2 | 8 | am_iomaster2_isr |
| I2C/SPI Master 3 | 9 | am_iomaster3_isr |
| I2C/SPI Master 4 | 10 | am_iomaster4_isr |
| I2C/SPI Master 5 | 11 | am_iomaster5_isr |
| BLE | 12 | am_ble_isr |
| GPIO | 13 | am_gpio_isr |
| Counter/Timers | 14 | am_ctimer_isr |
| UART0 | 15 | am_uart_isr |
| UART1 | 16 | am_uart1_isr |
| SCARD | 17 | am_scard_isr |
| ADC | 18 | am_adc_isr |
| PDM | 19 | am_pdm_isr |
| MSPI | 20 | am_mspi_isr |
| Stimer Capture/Overflow | 22 | am_stimer_isr |
| Stimer Compare 0 | 23 | am_stimer_cmpr0_isr |
| Stimer Compare 1 | 24 | am_stimer_cmpr1_isr |
| Stimer Compare 2 | 25 | am_stimer_cmpr2_isr |
| Stimer Compare 3 | 26 | am_stimer_cmpr3_isr |
| Stimer Compare 4 | 27 | am_stimer_cmpr4_isr |
| Stimer Compare 5 | 28 | am_stimer_cmpr5_isr |
| Stimer Compare 6 | 29 | am_stimer_cmpr6_isr |
| Stimer Compare 7 | 30 | am_stimer_cmpr7_isr |
| Clock Control | 31 | am_clkgen_isr |
To use any of the ISRs listed, make sure to prefix the function with extern "C" before the function declaration. For example:
extern "C" void am_pdm0_isr(void) {
...
}Note: all variables used within an ISR should also be declared with the volatile keyword.
The names of all of the ISRs can be found in the startup_gcc.c files for each variant of Apollo3 board.