Microcontroller Timer Circuit for Software-Emulated CAN FD Frames
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automotive microcontrollers without a dedicated CAN FD peripheral face challenges in controlling slave devices using the CAN FD Light communication protocol, requiring adaptation to implement high data rate and robust communication systems for sophisticated lighting systems while maintaining cost-effectiveness.
Innovation Solution
A microcontroller circuit is configured to transmit and receive CAN FD frames without a dedicated CAN FD peripheral by utilizing standard peripherals such as a timer module and DMA controllers, emulating the CAN FD interface via software, allowing for PWM signal generation and processing to emulate the CAN FD protocol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated CAN FD peripheral is used in the microcontroller, then communication reliability and data rate are improved, but device complexity and cost increase
Solution Approach 1:
The patent applies universality by enabling standard microcontroller peripherals (timers, PWM modules, GPIO) to perform multiple functions including CAN FD protocol implementation, PWM signal generation, and communication tasks. This allows the same hardware resources to serve both conventional control functions and advanced communication requirements without adding dedicated CAN FD peripherals.
Solution Approach 2:
The patent implements copying by creating a software-based CAN FD protocol stack that replicates the functionality of a dedicated CAN FD peripheral. The software emulation copies the essential communication protocols and data handling mechanisms of hardware CAN FD controllers, allowing standard microcontrollers to achieve CAN FD communication capabilities through software implementation.
2Productivity
If a dedicated CAN FD peripheral is implemented, then high data rate communication is achieved, but manufacturing cost increases
Solution Approach 1:
The patent employs this principle by replacing expensive dedicated CAN FD peripheral hardware with inexpensive software implementations running on standard microcontrollers. The software-based approach uses readily available, low-cost microcontroller units that can be mass-produced, eliminating the need for costly specialized communication hardware while maintaining high data rate capabilities through efficient software protocol stacks.
Solution Approach 2:
The patent substitutes hardware-based CAN FD communication mechanisms with software-based implementations. Instead of relying on dedicated communication hardware circuits, the system uses software protocols running on general-purpose processors, replacing specialized mechanical/electrical communication infrastructure with flexible software solutions that achieve similar or superior performance.
3Ease of manufacture
If standard peripherals are used to emulate CAN FD protocol, then cost is reduced, but implementation complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the CAN FD communication functionality into discrete software modules and layers. The protocol stack is segmented into protocol handling, data transmission, reception, and error management components, each implemented as separate software functions. This modular approach organizes the complex software implementation into manageable segments that can be developed, tested, and maintained independently.
Solution Approach 2:
The patent introduces intermediary software layers that mediate between the standard microcontroller peripherals and the CAN FD protocol requirements. These intermediary software components translate between the simple hardware capabilities and the complex communication protocol, acting as a buffer that simplifies the overall system architecture while enabling advanced communication features through standard hardware.
Data Source
Figure 1
Figure 2~4
Figure 3~8
AI summary
A circuit (106) comprises a first (24a) and a second (24b) memory, a processing unit (21) and a timer (22). The processing unit generates a sequence of bits encoding a CAN frame and processes the sequence of bits to detect a sequence of PWM periods. Each PWM period has a dominant portion and a recessive portion, and a total duration. The processing unit stores values of a first parameter of the PWM periods into the first memory, and values of a second parameter of the PWM periods into the second memory, wherein the first and second parameter define a shape of the PWM periods. The timer comprises a first register (220) which reads from the first memory a value of the first parameter of a current PWM period. The timer comprises a counter (221) which increases a count number and resets the count number as a function of the value of the first register. A value of the first parameter of a subsequent PWM period is stored into the first register as a function of the value of the first register. The timer comprises a second register (222) which reads from the second memory a value of the second parameter of the current PWM period, and compares the count number of the counter circuit to such value. The second register drives an output pin (230) to a dominant (resp., recessive) value as a function of said comparing the count number of the counter circuit to the value of the second register. A value of the second parameter of a subsequent PWM period is stored into the second register in response to the count number reaching the value stored in the first or second register.