Software Architecture¶

The software architecture defines the modular structure of the BrewMaster Pro 3000’s embedded control system. The architecture follows a layered approach with clear separation of concerns: safety-critical functions are isolated in dedicated modules, control algorithms are encapsulated for reusability, and user interface logic is decoupled from core brewing operations. This modular design enables independent testing, facilitates maintenance, and provides clear interfaces between components.

The architecture emphasizes fail-safe design principles. The Safety Monitor Module operates with the highest priority and can override all other subsystems. Module dependencies are carefully managed to prevent circular references and ensure deterministic behavior. The following diagram shows the architectural modules and their relationships:

Layers¶

Architectural Layer: Application Layer LAYER_APP

status: open

tags: layer

child needs: COMP_BREW_CTRL, COMP_UI_MODULE, INTF_BREW_CTRL_STATUS, INTF_USER_CMD

The application layer contains modules implementing user-facing functionality and brewing logic.

Component: User Interface Module COMP_UI_MODULE

status: open

tags: module, ui

parent needs: LAYER_APP

implements: SWREQ_BUTTON_INPUT

implemented by: IMPL_USER_CMD_PROVIDER

uses: INTF_GPIO, INTF_SPI_BUS

provides: INTF_USER_CMD

sends: SEQSTART_01, SEQSTART_03

sent by: SEQSTART_02, SEQSTART_10

sent by: SEQSHTDWN_06

Module handling all user interactions including button debouncing, LED status indicators, and display updates. Interfaces with the Brew Controller to send user commands (strength selection, start/stop).

$@startuml component "<size:12>Component</size>\n**User Interface**\n**Module**\n<size:10>COMP_UI_MODULE</size>" as COMP_UI_MODULE [[../coffee-machine/architecture.html#COMP_UI_MODULE]] #3498db node "<size:12>SW_Requirement</size>\n**Button Input**\n**Handler**\n<size:10>SWREQ_BUTTON_INPUT</size>" as SWREQ_BUTTON_INPUT [[../coffee-machine/sw_requirements.html#SWREQ_BUTTON_INPUT]] #a8f578 interface "<size:12>Interface</size>\n**GPIO Interface**\n<size:10>INTF_GPIO</size>" as INTF_GPIO [[../coffee-machine/architecture.html#INTF_GPIO]] #16a085 interface "<size:12>Interface</size>\n**SPI Bus**\n**Interface**\n<size:10>INTF_SPI_BUS</size>" as INTF_SPI_BUS [[../coffee-machine/architecture.html#INTF_SPI_BUS]] #16a085 interface "<size:12>Interface</size>\n**User Command**\n**Interface**\n<size:10>INTF_USER_CMD</size>" as INTF_USER_CMD [[../coffee-machine/architecture.html#INTF_USER_CMD]] #16a085 SWREQ_BUTTON_INPUT <-- COMP_UI_MODULE COMP_UI_MODULE --( INTF_GPIO COMP_UI_MODULE --( INTF_SPI_BUS COMP_UI_MODULE -- INTF_USER_CMD @enduml$

Component: Brew Controller Module COMP_BREW_CTRL

status: open

tags: module, control

parent needs: LAYER_APP

implements: SWREQ_BREW_STRENGTH

implemented by: IMPL_BREW_CTRL_STATUS_PROVIDER, IMPL_SAFETY_CMD_CONSUMER, IMPL_TEMP_STATUS_CONSUMER, IMPL_USER_CMD_CONSUMER

uses: INTF_GPIO, INTF_SAFETY_CMD, INTF_TEMP_STATUS, INTF_USER_CMD

provides: INTF_BREW_CTRL_STATUS

sends: SEQSTART_09

sent by: SEQSTART_08

sends: SEQSHTDWN_05

sent by: SEQSHTDWN_04

Module managing the brewing process state machine. States: IDLE, HEATING, BREWING, COMPLETE, ERROR. Controls pump and valve timing based on selected strength. Waits for temperature ready signal before initiating brew cycle. Monitors safety status continuously.

$@startuml component "<size:12>Component</size>\n**Brew Controller**\n**Module**\n<size:10>COMP_BREW_CTRL</size>" as COMP_BREW_CTRL [[../coffee-machine/architecture.html#COMP_BREW_CTRL]] #3498db node "<size:12>SW_Requirement</size>\n**Brew Strength**\n**Selection**\n<size:10>SWREQ_BREW_STRENGTH</size>" as SWREQ_BREW_STRENGTH [[../coffee-machine/sw_requirements.html#SWREQ_BREW_STRENGTH]] #a8f578 interface "<size:12>Interface</size>\n**GPIO Interface**\n<size:10>INTF_GPIO</size>" as INTF_GPIO [[../coffee-machine/architecture.html#INTF_GPIO]] #16a085 interface "<size:12>Interface</size>\n**Safety Command**\n**Interface**\n<size:10>INTF_SAFETY_CMD</size>" as INTF_SAFETY_CMD [[../coffee-machine/architecture.html#INTF_SAFETY_CMD]] #16a085 interface "<size:12>Interface</size>\n**Temperature**\n**Status**\n**Interface**\n<size:10>INTF_TEMP_STATUS</size>" as INTF_TEMP_STATUS [[../coffee-machine/architecture.html#INTF_TEMP_STATUS]] #16a085 interface "<size:12>Interface</size>\n**User Command**\n**Interface**\n<size:10>INTF_USER_CMD</size>" as INTF_USER_CMD [[../coffee-machine/architecture.html#INTF_USER_CMD]] #16a085 interface "<size:12>Interface</size>\n**Brew Controller**\n**Safety Status**\n**Interface**\n<size:10>INTF_BREW_CTRL_STATUS</size>" as INTF_BREW_CTRL_STATUS [[../coffee-machine/architecture.html#INTF_BREW_CTRL_STATUS]] #16a085 SWREQ_BREW_STRENGTH <-- COMP_BREW_CTRL COMP_BREW_CTRL --( INTF_GPIO COMP_BREW_CTRL --( INTF_SAFETY_CMD COMP_BREW_CTRL --( INTF_TEMP_STATUS COMP_BREW_CTRL --( INTF_USER_CMD COMP_BREW_CTRL -- INTF_BREW_CTRL_STATUS @enduml$

Interface: User Command Interface INTF_USER_CMD

status: open

tags: interface, ui

parent needs: LAYER_APP

implemented by: IMPL_USER_CMD_CONSUMER, IMPL_USER_CMD_ENUM, IMPL_USER_CMD_PROVIDER

used by: COMP_BREW_CTRL

provided by: COMP_UI_MODULE

Provider: User Interface Module

Consumer: Brew Controller Module

Description: User commands and settings passed from UI to the brewing state machine.

Commands:

START_BREW(strength: enum {WEAK, MEDIUM, STRONG})
STOP_BREW
SELECT_STRENGTH(strength: enum)

Protocol: Message queue with event-driven processing, debounced at UI layer

Interface: Brew Controller Safety Status Interface INTF_BREW_CTRL_STATUS

status: open

tags: interface, safety

parent needs: LAYER_APP

implemented by: IMPL_BREW_CTRL_STATUS, IMPL_BREW_CTRL_STATUS_CONSUMER, IMPL_BREW_CTRL_STATUS_PROVIDER

used by: COMP_SAFETY_MON

provided by: COMP_BREW_CTRL

Provider: Brew Controller Module

Consumer: Safety Monitor Module

Description: Heartbeat and fault status reported by the Brew Controller to the Safety Monitor for fault detection.

Data Elements:

module_id: uint8
heartbeat_counter: uint32 (incremented each cycle)
fault_flags: uint16 (bitfield of detected faults)
water_level: uint8 (0-100%)

Protocol: Polled by safety monitor at 10Hz

Architectural Layer: Control Layer LAYER_CTRL

status: open

tags: layer

child needs: COMP_TEMP_CTRL, INTF_TEMP_CTRL_STATUS, INTF_TEMP_STATUS

The control layer contains modules implementing closed-loop control algorithms for temperature regulation.

Component: Temperature Controller Module COMP_TEMP_CTRL

status: open

tags: module, control, safety

parent needs: LAYER_CTRL

implements: SWREQ_TEMP_REGULATION

implemented by: IMPL_SAFETY_CMD_CONSUMER, IMPL_SENSOR_DATA_CONSUMER, IMPL_TEMP_CTRL_STATUS_PROVIDER, IMPL_TEMP_STATUS_PROVIDER

uses: INTF_PWM_CTRL, INTF_SAFETY_CMD, INTF_SENSOR_DATA

provides: INTF_TEMP_CTRL_STATUS, INTF_TEMP_STATUS

sends: SEQSTART_07

sent by: SEQSTART_06

sends: SEQSHTDWN_03

sent by: SEQSHTDWN_02

Module responsible for PID-based temperature control. Interfaces:

Input: Temperature sensor (ADC)
Output: Heating element PWM control
Safety: Reports temperature status to Safety Monitor
Safety: Responds to emergency shutdown commands

$@startuml component "<size:12>Component</size>\n**Temperature**\n**Controller**\n**Module**\n<size:10>COMP_TEMP_CTRL</size>" as COMP_TEMP_CTRL [[../coffee-machine/architecture.html#COMP_TEMP_CTRL]] #3498db node "<size:12>SW_Requirement</size>\n**Temperature**\n**Regulation**\n<size:10>SWREQ_TEMP_REGULATION</size>" as SWREQ_TEMP_REGULATION [[../coffee-machine/sw_requirements.html#SWREQ_TEMP_REGULATION]] #a8f578 interface "<size:12>Interface</size>\n**PWM Control**\n**Interface**\n<size:10>INTF_PWM_CTRL</size>" as INTF_PWM_CTRL [[../coffee-machine/architecture.html#INTF_PWM_CTRL]] #16a085 interface "<size:12>Interface</size>\n**Safety Command**\n**Interface**\n<size:10>INTF_SAFETY_CMD</size>" as INTF_SAFETY_CMD [[../coffee-machine/architecture.html#INTF_SAFETY_CMD]] #16a085 interface "<size:12>Interface</size>\n**Sensor Data**\n**Interface**\n<size:10>INTF_SENSOR_DATA</size>" as INTF_SENSOR_DATA [[../coffee-machine/architecture.html#INTF_SENSOR_DATA]] #16a085 interface "<size:12>Interface</size>\n**Temperature**\n**Controller**\n**Safety Status**\n**Interface**\n<size:10>INTF_TEMP_CTRL_STATUS</size>" as INTF_TEMP_CTRL_STATUS [[../coffee-machine/architecture.html#INTF_TEMP_CTRL_STATUS]] #16a085 interface "<size:12>Interface</size>\n**Temperature**\n**Status**\n**Interface**\n<size:10>INTF_TEMP_STATUS</size>" as INTF_TEMP_STATUS [[../coffee-machine/architecture.html#INTF_TEMP_STATUS]] #16a085 SWREQ_TEMP_REGULATION <-- COMP_TEMP_CTRL COMP_TEMP_CTRL --( INTF_PWM_CTRL COMP_TEMP_CTRL --( INTF_SAFETY_CMD COMP_TEMP_CTRL --( INTF_SENSOR_DATA COMP_TEMP_CTRL -- INTF_TEMP_CTRL_STATUS COMP_TEMP_CTRL -- INTF_TEMP_STATUS @enduml$

Interface: Temperature Status Interface INTF_TEMP_STATUS

status: open

tags: interface, control

parent needs: LAYER_CTRL

implemented by: IMPL_TEMP_STATUS, IMPL_TEMP_STATUS_CONSUMER, IMPL_TEMP_STATUS_PROVIDER

used by: COMP_BREW_CTRL

provided by: COMP_TEMP_CTRL

Provider: Temperature Controller Module

Consumer: Brew Controller Module

Description: Provides current temperature readings and heating status to the brew controller.

Data Elements:

current_temp: int16 (°C × 10 for 0.1°C resolution)
target_temp: int16 (°C × 10)
is_ready: bool (true when within target range)
heating_active: bool

Protocol: Shared memory with atomic updates, 100ms refresh rate

Interface: Temperature Controller Safety Status Interface INTF_TEMP_CTRL_STATUS

status: open

tags: interface, safety

parent needs: LAYER_CTRL

implemented by: IMPL_TEMP_CTRL_STATUS, IMPL_TEMP_CTRL_STATUS_CONSUMER, IMPL_TEMP_CTRL_STATUS_PROVIDER

used by: COMP_SAFETY_MON

provided by: COMP_TEMP_CTRL

Provider: Temperature Controller Module

Consumer: Safety Monitor Module

Description: Heartbeat and fault status reported by the Temperature Controller to the Safety Monitor for fault detection.

Data Elements:

module_id: uint8
heartbeat_counter: uint32 (incremented each cycle)
fault_flags: uint16 (bitfield of detected faults)
temperature_value: int16 (current measured temperature)

Protocol: Polled by safety monitor at 10Hz

Architectural Layer: Safety Layer LAYER_SAFETY

status: open

tags: layer

child needs: COMP_SAFETY_MON, INTF_SAFETY_CMD

The safety layer contains modules with the highest execution priority, performing continuous safety monitoring and enforcing fail-safe shutdown procedures.

Component: Safety Monitor Module COMP_SAFETY_MON

status: open

tags: module, safety

parent needs: LAYER_SAFETY

implements: SWREQ_OVERTEMP_SHUTDOWN, SWREQ_WATER_LEVEL

implemented by: IMPL_BREW_CTRL_STATUS_CONSUMER, IMPL_SAFETY_CMD_PROVIDER, IMPL_SENSOR_DATA_CONSUMER, IMPL_TEMP_CTRL_STATUS_CONSUMER

uses: INTF_BREW_CTRL_STATUS, INTF_SENSOR_DATA, INTF_TEMP_CTRL_STATUS

provides: INTF_SAFETY_CMD

sends: SEQSTART_04, SEQSTART_06, SEQSTART_08, SEQSTART_10

sent by: SEQSTART_03, SEQSTART_05, SEQSTART_07, SEQSTART_09

sends: SEQSHTDWN_02, SEQSHTDWN_04, SEQSHTDWN_06

sent by: SEQSHTDWN_01, SEQSHTDWN_03, SEQSHTDWN_05

Module performing continuous safety checks on temperature and water level. Implements fail-safe shutdown procedures.

$@startuml component "<size:12>Component</size>\n**Safety Monitor**\n**Module**\n<size:10>COMP_SAFETY_MON</size>" as COMP_SAFETY_MON [[../coffee-machine/architecture.html#COMP_SAFETY_MON]] #3498db node "<size:12>SW_Requirement</size>\n**Over-**\n**Temperature**\n**Shutdown**\n<size:10>SWREQ_OVERTEMP_SHUTDOWN</size>" as SWREQ_OVERTEMP_SHUTDOWN [[../coffee-machine/sw_requirements.html#SWREQ_OVERTEMP_SHUTDOWN]] #a8f578 node "<size:12>SW_Requirement</size>\n**Water Level**\n**Monitoring**\n<size:10>SWREQ_WATER_LEVEL</size>" as SWREQ_WATER_LEVEL [[../coffee-machine/sw_requirements.html#SWREQ_WATER_LEVEL]] #a8f578 interface "<size:12>Interface</size>\n**Brew Controller**\n**Safety Status**\n**Interface**\n<size:10>INTF_BREW_CTRL_STATUS</size>" as INTF_BREW_CTRL_STATUS [[../coffee-machine/architecture.html#INTF_BREW_CTRL_STATUS]] #16a085 interface "<size:12>Interface</size>\n**Sensor Data**\n**Interface**\n<size:10>INTF_SENSOR_DATA</size>" as INTF_SENSOR_DATA [[../coffee-machine/architecture.html#INTF_SENSOR_DATA]] #16a085 interface "<size:12>Interface</size>\n**Temperature**\n**Controller**\n**Safety Status**\n**Interface**\n<size:10>INTF_TEMP_CTRL_STATUS</size>" as INTF_TEMP_CTRL_STATUS [[../coffee-machine/architecture.html#INTF_TEMP_CTRL_STATUS]] #16a085 interface "<size:12>Interface</size>\n**Safety Command**\n**Interface**\n<size:10>INTF_SAFETY_CMD</size>" as INTF_SAFETY_CMD [[../coffee-machine/architecture.html#INTF_SAFETY_CMD]] #16a085 SWREQ_OVERTEMP_SHUTDOWN <-- COMP_SAFETY_MON SWREQ_WATER_LEVEL <-- COMP_SAFETY_MON COMP_SAFETY_MON --( INTF_BREW_CTRL_STATUS COMP_SAFETY_MON --( INTF_SENSOR_DATA COMP_SAFETY_MON --( INTF_TEMP_CTRL_STATUS COMP_SAFETY_MON -- INTF_SAFETY_CMD @enduml$

Interface: Safety Command Interface INTF_SAFETY_CMD

status: open

tags: interface, safety

parent needs: LAYER_SAFETY

implemented by: IMPL_SAFETY_CMD_CONSUMER, IMPL_SAFETY_CMD_ENUM, IMPL_SAFETY_CMD_PROVIDER

used by: COMP_BREW_CTRL, COMP_TEMP_CTRL

provided by: COMP_SAFETY_MON

Provider: Safety Monitor Module

Consumers: Temperature Controller, Brew Controller

Description: Emergency shutdown commands from safety monitor to all controlled subsystems.

Commands:

EMERGENCY_STOP: Immediate shutdown (<100ms response required)
RESUME_NORMAL: Clear emergency state after fault resolved

Protocol: Interrupt-driven with hardware watchdog backup, highest priority

Architectural Layer: Hardware Abstraction Layer LAYER_HAL

status: open

tags: layer

child needs: COMP_ADC_DRV, COMP_GPIO_DRV, COMP_PWM_DRV, COMP_SPI_DRV, INTF_GPIO, INTF_PWM_CTRL, INTF_SENSOR_DATA, INTF_SPI_BUS

The HAL provides abstraction over physical hardware, offering consistent APIs for sensor reading and actuator control.

Component: ADC Driver COMP_ADC_DRV

status: open

tags: module, hardware, driver

parent needs: LAYER_HAL

implemented by: IMPL_SENSOR_DATA_PROVIDER

provides: INTF_SENSOR_DATA

sends: SEQSTART_02, SEQSTART_05

sent by: SEQSTART_01, SEQSTART_04

sends: SEQSHTDWN_01

Driver for the 12-bit ADC peripheral. Manages DMA-based sampling at 100Hz with double buffering, automatic averaging, and outlier rejection. Channels:

Channel 0: Temperature sensor (NTC thermistor)
Channel 1: Water level sensor (capacitive)

$@startuml component "<size:12>Component</size>\n**ADC Driver**\n<size:10>COMP_ADC_DRV</size>" as COMP_ADC_DRV [[../coffee-machine/architecture.html#COMP_ADC_DRV]] #3498db interface "<size:12>Interface</size>\n**Sensor Data**\n**Interface**\n<size:10>INTF_SENSOR_DATA</size>" as INTF_SENSOR_DATA [[../coffee-machine/architecture.html#INTF_SENSOR_DATA]] #16a085 COMP_ADC_DRV -- INTF_SENSOR_DATA @enduml$

Component: PWM Driver COMP_PWM_DRV

status: open

tags: module, hardware, driver

parent needs: LAYER_HAL

implemented by: IMPL_PWM_CTRL

provides: INTF_PWM_CTRL

Driver for PWM output generation. Controls the heating element via variable duty cycle (0–100%) at 1 kHz switching frequency. Supports soft-start ramp to prevent inrush current.

$@startuml component "<size:12>Component</size>\n**PWM Driver**\n<size:10>COMP_PWM_DRV</size>" as COMP_PWM_DRV [[../coffee-machine/architecture.html#COMP_PWM_DRV]] #3498db interface "<size:12>Interface</size>\n**PWM Control**\n**Interface**\n<size:10>INTF_PWM_CTRL</size>" as INTF_PWM_CTRL [[../coffee-machine/architecture.html#INTF_PWM_CTRL]] #16a085 COMP_PWM_DRV -- INTF_PWM_CTRL @enduml$

Component: GPIO Driver COMP_GPIO_DRV

status: open

tags: module, hardware, driver

parent needs: LAYER_HAL

implemented by: IMPL_GPIO_CTRL

provides: INTF_GPIO

Driver for general-purpose I/O pins. Manages:

Output: Pump motor control (on/off)
Output: Brew valve solenoid (open/close)
Input: Button inputs (directly active-low with internal pull-ups)
Output: LED status indicators

$@startuml component "<size:12>Component</size>\n**GPIO Driver**\n<size:10>COMP_GPIO_DRV</size>" as COMP_GPIO_DRV [[../coffee-machine/architecture.html#COMP_GPIO_DRV]] #3498db interface "<size:12>Interface</size>\n**GPIO Interface**\n<size:10>INTF_GPIO</size>" as INTF_GPIO [[../coffee-machine/architecture.html#INTF_GPIO]] #16a085 COMP_GPIO_DRV -- INTF_GPIO @enduml$

Component: SPI Driver COMP_SPI_DRV

status: open

tags: module, hardware, driver

parent needs: LAYER_HAL

implemented by: IMPL_SPI_BUS

provides: INTF_SPI_BUS

Driver for the SPI bus peripheral. Provides communication with the front-panel display controller (OLED) for status and menu rendering. Operates at 4 MHz with DMA for frame-buffer transfers.

$@startuml component "<size:12>Component</size>\n**SPI Driver**\n<size:10>COMP_SPI_DRV</size>" as COMP_SPI_DRV [[../coffee-machine/architecture.html#COMP_SPI_DRV]] #3498db interface "<size:12>Interface</size>\n**SPI Bus**\n**Interface**\n<size:10>INTF_SPI_BUS</size>" as INTF_SPI_BUS [[../coffee-machine/architecture.html#INTF_SPI_BUS]] #16a085 COMP_SPI_DRV -- INTF_SPI_BUS @enduml$

Interface: PWM Control Interface INTF_PWM_CTRL

status: open

tags: interface, hardware

parent needs: LAYER_HAL

implemented by: IMPL_PWM_CHANNEL, IMPL_PWM_CTRL

used by: COMP_TEMP_CTRL

provided by: COMP_PWM_DRV

Provider: PWM Driver

Consumer: Temperature Controller Module

Description: Controls PWM output channels for heating element regulation.

Operations:

set_duty_cycle(channel: uint8, duty: uint16) — 0–10000 (0.01% resolution)
enable(channel: uint8)
disable(channel: uint8)

Protocol: Direct register-mapped API, immediate effect

Interface: GPIO Interface INTF_GPIO

status: open

tags: interface, hardware

parent needs: LAYER_HAL

implemented by: IMPL_GPIO_CTRL, IMPL_GPIO_EDGE, IMPL_GPIO_PIN

used by: COMP_BREW_CTRL, COMP_UI_MODULE

provided by: COMP_GPIO_DRV

Provider: GPIO Driver

Consumers: User Interface Module, Brew Controller Module

Description: Digital I/O abstraction for discrete signals — pump motor, brew valve, buttons, and LED indicators.

Operations:

set_pin(pin: GpioPin, state: bool)
read_pin(pin: GpioPin) → bool
register_interrupt(pin: GpioPin, edge: Edge, callback: fn())

Protocol: Direct register-mapped API with interrupt support

Interface: SPI Bus Interface INTF_SPI_BUS

status: open

tags: interface, hardware

parent needs: LAYER_HAL

implemented by: IMPL_SPI_BUS

used by: COMP_UI_MODULE

provided by: COMP_SPI_DRV

Provider: SPI Driver

Consumer: User Interface Module

Description: SPI bus access for communication with the front-panel OLED display controller.

Operations:

transfer(tx_buf: &[u8], rx_buf: &mut [u8])
write_dma(buf: &[u8]) — non-blocking DMA transfer
busy() → bool

Protocol: Full-duplex SPI Mode 0, 4 MHz clock, DMA-capable

Interface: Sensor Data Interface INTF_SENSOR_DATA

status: open

tags: interface, hardware

parent needs: LAYER_HAL

implemented by: IMPL_SENSOR_DATA, IMPL_SENSOR_DATA_CONSUMER, IMPL_SENSOR_DATA_PROVIDER

used by: COMP_SAFETY_MON, COMP_TEMP_CTRL

provided by: COMP_ADC_DRV

Provider: Hardware sensors (temperature, water level)

Consumers: Temperature Controller, Safety Monitor

Description: Raw sensor readings from hardware via ADC.

Data Elements:

temp_sensor_raw: uint16 (ADC value 0-4095)
water_level_raw: uint16 (ADC value 0-4095)
sensor_timestamp: uint32 (milliseconds)

Protocol: ADC DMA with double buffering, 100Hz sampling rate

Static View¶

@startuml

' Config

top to bottom direction

' Nodes definition

package "<size:12>Architectural Layer</size>\n**Application**\n**Layer**\n<size:10>LAYER_APP</size>" as LAYER_APP [[../coffee-machine/architecture.html#LAYER_APP]] #8e44ad{
'child needs:
component "<size:12>Component</size>\n**Brew Controller**\n**Module**\n<size:10>COMP_BREW_CTRL</size>" as COMP_BREW_CTRL [[../coffee-machine/architecture.html#COMP_BREW_CTRL]] #3498db
component "<size:12>Component</size>\n**User Interface**\n**Module**\n<size:10>COMP_UI_MODULE</size>" as COMP_UI_MODULE [[../coffee-machine/architecture.html#COMP_UI_MODULE]] #3498db
interface "<size:12>Interface</size>\n**Brew Controller**\n**Safety Status**\n**Interface**\n<size:10>INTF_BREW_CTRL_STATUS</size>" as INTF_BREW_CTRL_STATUS [[../coffee-machine/architecture.html#INTF_BREW_CTRL_STATUS]] #16a085
interface "<size:12>Interface</size>\n**User Command**\n**Interface**\n<size:10>INTF_USER_CMD</size>" as INTF_USER_CMD [[../coffee-machine/architecture.html#INTF_USER_CMD]] #16a085
}
package "<size:12>Architectural Layer</size>\n**Control Layer**\n<size:10>LAYER_CTRL</size>" as LAYER_CTRL [[../coffee-machine/architecture.html#LAYER_CTRL]] #8e44ad{
'child needs:
component "<size:12>Component</size>\n**Temperature**\n**Controller**\n**Module**\n<size:10>COMP_TEMP_CTRL</size>" as COMP_TEMP_CTRL [[../coffee-machine/architecture.html#COMP_TEMP_CTRL]] #3498db
interface "<size:12>Interface</size>\n**Temperature**\n**Controller**\n**Safety Status**\n**Interface**\n<size:10>INTF_TEMP_CTRL_STATUS</size>" as INTF_TEMP_CTRL_STATUS [[../coffee-machine/architecture.html#INTF_TEMP_CTRL_STATUS]] #16a085
interface "<size:12>Interface</size>\n**Temperature**\n**Status**\n**Interface**\n<size:10>INTF_TEMP_STATUS</size>" as INTF_TEMP_STATUS [[../coffee-machine/architecture.html#INTF_TEMP_STATUS]] #16a085
}
package "<size:12>Architectural Layer</size>\n**Safety Layer**\n<size:10>LAYER_SAFETY</size>" as LAYER_SAFETY [[../coffee-machine/architecture.html#LAYER_SAFETY]] #8e44ad{
'child needs:
component "<size:12>Component</size>\n**Safety Monitor**\n**Module**\n<size:10>COMP_SAFETY_MON</size>" as COMP_SAFETY_MON [[../coffee-machine/architecture.html#COMP_SAFETY_MON]] #3498db
interface "<size:12>Interface</size>\n**Safety Command**\n**Interface**\n<size:10>INTF_SAFETY_CMD</size>" as INTF_SAFETY_CMD [[../coffee-machine/architecture.html#INTF_SAFETY_CMD]] #16a085
}
package "<size:12>Architectural Layer</size>\n**Hardware**\n**Abstraction**\n**Layer**\n<size:10>LAYER_HAL</size>" as LAYER_HAL [[../coffee-machine/architecture.html#LAYER_HAL]] #8e44ad{
'child needs:
component "<size:12>Component</size>\n**ADC Driver**\n<size:10>COMP_ADC_DRV</size>" as COMP_ADC_DRV [[../coffee-machine/architecture.html#COMP_ADC_DRV]] #3498db
component "<size:12>Component</size>\n**GPIO Driver**\n<size:10>COMP_GPIO_DRV</size>" as COMP_GPIO_DRV [[../coffee-machine/architecture.html#COMP_GPIO_DRV]] #3498db
component "<size:12>Component</size>\n**PWM Driver**\n<size:10>COMP_PWM_DRV</size>" as COMP_PWM_DRV [[../coffee-machine/architecture.html#COMP_PWM_DRV]] #3498db
component "<size:12>Component</size>\n**SPI Driver**\n<size:10>COMP_SPI_DRV</size>" as COMP_SPI_DRV [[../coffee-machine/architecture.html#COMP_SPI_DRV]] #3498db
interface "<size:12>Interface</size>\n**GPIO Interface**\n<size:10>INTF_GPIO</size>" as INTF_GPIO [[../coffee-machine/architecture.html#INTF_GPIO]] #16a085
interface "<size:12>Interface</size>\n**PWM Control**\n**Interface**\n<size:10>INTF_PWM_CTRL</size>" as INTF_PWM_CTRL [[../coffee-machine/architecture.html#INTF_PWM_CTRL]] #16a085
interface "<size:12>Interface</size>\n**Sensor Data**\n**Interface**\n<size:10>INTF_SENSOR_DATA</size>" as INTF_SENSOR_DATA [[../coffee-machine/architecture.html#INTF_SENSOR_DATA]] #16a085
interface "<size:12>Interface</size>\n**SPI Bus**\n**Interface**\n<size:10>INTF_SPI_BUS</size>" as INTF_SPI_BUS [[../coffee-machine/architecture.html#INTF_SPI_BUS]] #16a085
}

' Connection definition

COMP_UI_MODULE -[dashed]-( INTF_GPIO: uses\n
COMP_UI_MODULE -[dashed]-( INTF_SPI_BUS: uses\n
COMP_BREW_CTRL -[dashed]-( INTF_GPIO: uses\n
COMP_BREW_CTRL -[dashed]-( INTF_SAFETY_CMD: uses\n
COMP_BREW_CTRL -[dashed]-( INTF_TEMP_STATUS: uses\n
COMP_BREW_CTRL -[dashed]-( INTF_USER_CMD: uses\n
COMP_TEMP_CTRL -[dashed]-( INTF_PWM_CTRL: uses\n
COMP_TEMP_CTRL -[dashed]-( INTF_SAFETY_CMD: uses\n
COMP_TEMP_CTRL -[dashed]-( INTF_SENSOR_DATA: uses\n
COMP_SAFETY_MON -[dashed]-( INTF_BREW_CTRL_STATUS: uses\n
COMP_SAFETY_MON -[dashed]-( INTF_SENSOR_DATA: uses\n
COMP_SAFETY_MON -[dashed]-( INTF_TEMP_CTRL_STATUS: uses\n
INTF_USER_CMD -[bold]- COMP_UI_MODULE: provided by\n
INTF_BREW_CTRL_STATUS -[bold]- COMP_BREW_CTRL: provided by\n
INTF_TEMP_STATUS -[bold]- COMP_TEMP_CTRL: provided by\n
INTF_TEMP_CTRL_STATUS -[bold]- COMP_TEMP_CTRL: provided by\n
INTF_SAFETY_CMD -[bold]- COMP_SAFETY_MON: provided by\n
INTF_PWM_CTRL -[bold]- COMP_PWM_DRV: provided by\n
INTF_GPIO -[bold]- COMP_GPIO_DRV: provided by\n
INTF_SPI_BUS -[bold]- COMP_SPI_DRV: provided by\n
INTF_SENSOR_DATA -[bold]- COMP_ADC_DRV: provided by\n

@enduml

Dynamic View¶

The sequence diagrams below show how the architectural components interact at runtime. Participants map directly to the components defined in the Static View.

The diagrams are generated by needsequence, which traverses the startup_calls / shutdown_calls links defined on each component need. Each seq_msg (SEQSTART_01) need in the chain represents one message; odd hops are participants, even hops are messages.

Startup Sequence¶

On power-on the system initialises hardware, validates initial sensor readings, then brings all control modules online in dependency order before signalling readiness to the user.

The sequence message needs (SEQSTART_01–SEQSTART_10) are defined below. COMP_UI_MODULE is the starting participant.

@startuml

' Nodes definition

participant "User Interface Module" as COMP_UI_MODULE
participant "ADC Driver" as COMP_ADC_DRV
participant "Safety Monitor Module" as COMP_SAFETY_MON
participant "Temperature Controller Module" as COMP_TEMP_CTRL
participant "Brew Controller Module" as COMP_BREW_CTRL

' Connection definition

COMP_UI_MODULE -> COMP_ADC_DRV: init()
COMP_ADC_DRV -> COMP_UI_MODULE: init_ok
COMP_ADC_DRV -> COMP_SAFETY_MON: temp=22°C, water_level=85%
COMP_SAFETY_MON -> COMP_ADC_DRV: read_sensors()
COMP_SAFETY_MON -> COMP_TEMP_CTRL: start() — Temp Controller
COMP_TEMP_CTRL -> COMP_SAFETY_MON: started (INTF_TEMP_CTRL_STATUS heartbeat)
COMP_SAFETY_MON -> COMP_BREW_CTRL: start() — Brew Controller
COMP_BREW_CTRL -> COMP_SAFETY_MON: started (INTF_BREW_CTRL_STATUS heartbeat)
COMP_SAFETY_MON -> COMP_UI_MODULE: system_ready
COMP_UI_MODULE -> COMP_SAFETY_MON: start() — Safety Monitor

@enduml — Startup Sequence¶

Safety Shutdown Sequence¶

If the Safety Monitor detects an over-temperature condition it issues an EMERGENCY_STOP command on INTF_SAFETY_CMD to all controlled subsystems. All modules must respond within 100 ms.

The sequence message needs (SEQSHTDWN_01–SEQSHTDWN_06) are defined below. COMP_ADC_DRV is the starting participant (it is the source of the over-temperature sensor reading).

@startuml

' Nodes definition

participant "ADC Driver" as COMP_ADC_DRV
participant "Safety Monitor Module" as COMP_SAFETY_MON
participant "Temperature Controller Module" as COMP_TEMP_CTRL
participant "Brew Controller Module" as COMP_BREW_CTRL

' Connection definition

COMP_ADC_DRV -> COMP_SAFETY_MON: temp=102°C (INTF_SENSOR_DATA — over-temp)
COMP_SAFETY_MON -> COMP_TEMP_CTRL: EMERGENCY_STOP → Temp Controller
COMP_TEMP_CTRL -> COMP_SAFETY_MON: fault_flags=OVERTEMP (INTF_TEMP_CTRL_STATUS)
COMP_SAFETY_MON -> COMP_BREW_CTRL: EMERGENCY_STOP → Brew Controller
COMP_BREW_CTRL -> COMP_SAFETY_MON: fault_flags=ABORT (INTF_BREW_CTRL_STATUS)
COMP_SAFETY_MON -> COMP_UI_MODULE: fault_event(OVERTEMP)

@enduml — Safety Shutdown Sequence¶