User Manual

Apollo3 Blue Datasheet

DS-A3-0p9p1 Page 68 of 909 2019 Ambiq Micro, Inc.

3. MCU Core Details

At the center of the Apollo3 Blue MCU is a 32-bit ARM Cortex-M4 core with the floating point option. This

3-stage pipeline implementation of the ARM v7-M architecture offers highly efficient processing in a very

low power design. The ARM M DAP enables debugging access via a Serial Wire Interface from outside of

the MCU which allows access to all of the memory and peripheral devices of the MCU. The M4 core offers

some other advantages including:

▪ Single 4 GB memory architecture with all Peripherals being memory-mapped

▪ Low-Power Consumption Modes:

- Active

-Sleep

- Deep-Sleep

-Power-Off

▪ Interrupts and Events

- NVIC – interrupt controller

- WIC – Wake-Up Interrupt Controller

- Sleep-on-Exit (reduces interrupt overhead, used in an ISR SW structure)

- WFI (enter sleep modes, wait for interrupts)

The following sections provide behavioral and performance details about each of the peripherals controlled

by the MCU core. Where multiple instances of a peripheral exist on Apollo3 Blue MCU (e.g., the I

C/SPI

master modules), base memory addresses for the registers are provided for each and noted as

INSTANCE 0, INSTANCE 1, etc.

3.1 Interrupts

Within the MCU, multiple peripherals can generate interrupts. In some cases, a single peripheral may be

able to generate multiple different interrupts. Each interrupt signal generated by a peripheral is connected

back to the M4 core in two places. First, the interrupts are connected to the Nested Vectored Interrupt

Controller, NVIC, in the core. This connection provides the standard changes to program flow associated

with interrupt processing. Additionally, they are connected to the WIC outside of the core, allowing the

interrupt sources to wake the M4 core when it is in a deep sleep (SRPG) mode.

The MCU supports the M4 NMI as well as the normal interrupt types. For details on the Interrupt model of

the M4, please see the “Cortex-M4 Devices Generic User Guide,” document number DUI0553A.

Below is the M4 Vector Table for Apollo3 Blue MCU: