Host Communication Standards Clause Samples

Host Communication Standards. An embedded system is often controlled from a host computer. During development and test- ing, there is a need to read out logs and other relevant data, and there might also be a need to send commands to the embedded system during test runs. Depending on the application, there might also be a need for communication with a host computer during normal use. As an example, a UAV might record telemetry data during flight, which can be downloaded to a host after landing. For these situations, there must be an interface for connecting the embedded system to the host computer. There are a number of suitable standards with different characteristics. The interface standard should be chosen based on the following considerations: Performance: The performance spectrum of the different communication interfaces is huge. Identifying performance requirements are, therefore, important. Availability on host computer. It is often important that the embedded device can be connected to an ordinary PC without extra equipment. If this is the case, one of the interfaces found on common PCs should be chosen. Ease of implementation. Software stack complexity can be a limiting factor for small embedded systems with limited memory and processing power. Physical requirements, such as connector footprint size and high-speed or RF considerations can also influ- ence choice of interface. This section will go through the most common interface standards used for the purposes mentioned above, and discuss their characteristics. The are two main categories: Wired and wireless. The section will discuss both. USB has the following technical characteristics: Complex interface, although software stacks exist for small embedded devices. If high performance is required, the software and physical design becomes more challenging. Ethernet has the following technical characteristics: High performance interface. The highest performing Ethernet standard today is 400 Gb/s, although 10 or 100 Mb/s is more likely for an embedded system. Widely available, although the infrastructure requirements are slightly higher than for USB. An Ethernet switch might be necessary, and some laptops are sold without an Ethernet port. RD232 has the following technical characteristics: Used to be widely available, although modern laptops no longer ship with an RS232 port. RS232 to USB converters are available. Very simple software stack, can be implemented easily using almost no memory and processing power. Simple physical im...