HAL and APIs
CEC commands on the TV can also be processed by general-purpose hardware. CEC Input/Output (IO) access, along with signaling and bit
timing operations can be managed via hardware, while command messages (opcodes), frame
and flow controls (including vendor specific flows) are handled via library software
These libraries are either custom developed or purchased off-the-shelf and integrated with custom device software. The Hardware Abstraction Layer (HAL) provides necessary glue logic for Application Programming Interface (API) support for sending and Receiving CEC commands.
Figure 3: Typical software implementation architecture
Emerging off-the-shelf CEC software technologies (Figure 3), such as those provided by Simplay Labs, support fully interoperable implementations, and also support a full suite of consumer-relevant functions.
CEC interoperability verification testing and test tools
Product performance test coverage is an important aspect of verification thoroughness. The main goal of any testing regimen is to find failures, and test coverage is a way to show how well verification has "covered" a given function of the system.
The quality of any CEC implementation, as perceived by the consumer, is a key measurement of the effectiveness of the CEC test process. The goal of any CEC test strategy must be to meet these Quality of Experience (QoE) expectations. However, consumers' expectations of quality are often difficult to measure concisely. QoE expectations can vary according to many factors such as the application environment, the user's familiarity with the HD component, and its price point.
The application testing environment must address both technical and behavioral considerations. Price is also a factor since many consumers will demand higher quality from more expensive equipment, even though a device's cost may be driven by features that do not directly improve quality.
Consumers who are highly familiar with HD entertainment systems may tend to tolerate such things as minor interoperability problems, but less HD-literate customers might consider any user problem a "fault." These issues present major challenges to CE manufacturers, who have to strike a compromise between maximizing customer satisfaction and minimizing time-to-market.
Therefore, CEC application-level testing demands that new tools be developed to support time-to-market concerns, as well as interoperability and functionality requirements. Emerging CEC performance testing tools, such as those supplied by Simplay Labs, enable streamlined designer testing and a more robust level of CEC interoperability testing, including:
Next: The Simplay HD CEC program and logo
- Automated command logical error testing (e.g., send deck control start and again send deck control start),
- Bus stress testing including standard and vendor-specific commands,
- Bit timing testing,
- ACK (message length) and command parameter range testing,
- Hot plug behavior testing,
- Logical errors/stress testing,
- Random errors and noise on the CEC wire testing,
- CEC bus blocking testing,
- Automatic regression testing,
- Device reporting capabilities testing,
- LA (Logical Address) allocation testing,
- Conflict checking when HDMI port is changed