ICOM module documentation

Overview

ICOM (Internal Communication) is a simple C language internal communication module, which is used to realize efficient bidirectional data communication in embedded systems. It provides a communication mechanism based on shared memory to support multi-channel data transmission and state management.

Core features

Bidirectional communication : Support for separate send and receive channels
State management : Provides four channel states: initialized, idle, busy, and error
Data length control : Supports dynamic data length setting and validation
Live detection : Automatically detects the online state of the communication peer
Cache control : Supports cache invalidation and writeback operations
Multi-channel support : Multiple send and receive channels can be configured

Architectural Design

Communication protocol format

offset	field	size	description
0	Flag	4	Channel status flag
4	Tcnt	4	Send channel count
8	Rcnt	4	Receive channel count
12	Dlen	4	data length
16	Data	N	actual data

State Machine design

INIT : The initial state
BUSY : Busy (in data transfer)
IDLE : Idle state (transferable)
ERROR : An error state

API explained in detail

Initialization functions

int icom_init(ICOM *icom);

Initialize the ICOM module and configure the sending and receiving channels.

Task handlers

int icom_task(ICOM *icom);

Handle the periodic tasks of the ICOM module, including online state detection and data reception processing.

Data sending function

int icom_transmit(ICOM *icom, uint16_t channel, uint8_t *data, uint32_t length);

Send data over the specified channel.

Data receiving functions

int icom_receive(ICOM *icom, uint16_t channel, uint8_t *data, uint32_t *length);

Handle the periodic tasks of the ICOM module, including online state detection and data reception processing. Receives data from the specified channel.

Online presence checks

int icom_txchannel_online(ICOM *icom, uint16_t channel, uint8_t *online);
int icom_rxchannel_online(ICOM *icom, uint16_t channel, uint8_t *online);

Check the online status of the send/receive channel.

Instructions

Initialize the ICOM struct and configure the channel
Call icom_init() for initialization
Periodic calls to icom_task() for state management and data reception processing
Use icom_transmit() to send data
Use icom_receive() to receive data

Advanced features

Manual receive mode: You can manually check the receive status without using callbacks
Cache control: Cache control via 'inv' and 'wbinv' callbacks
Private data: Each channel maintains 4 private data words for extended functionality

Use cases

Inter-Processor Communication (IPC)
Data exchange between multiple cores
Modular system component communication
Embedded systems that require shared memory communication

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