• Once having issued a PTM Request Message, the Upstream Port must not issue another PTM Request Message prior to the receipt of a PTM Response Message, PTM ResponseD Message, Reset, or the passage of 100 μs without a corresponding PTM Message from the Downstream Port. • Upon receiving a PTM Response, the Upstream Port must wait at least 1 μs before issuing another PTM Request Message. • For Multi-Function Devices (MFDs) containing multiple PTM Requesters, the Upstream Port associated with that MFD must issue a single PTM dialog during each PTM context refresh. PTM Requesters within the MFD maintain their individual PTM contexts using this one, Device-wide PTM dialog. The mechanism for refreshing multiple PTM contexts from one PTM dialog is implementation specific. 翻译一下

• 一旦发出PTM请求消息，上游端口在收到PTM响应消息、PTM ResponseD消息、复位或100μs内没有来自下游端口的相应PTM消息之前，不能再发出另一个PTM请求消息。
• 收到PTM响应后，上游端口必须等待至少1μs才能再次发出PTM请求消息。
• 对于包含多个PTM请求者的多功能设备（MFDs），与该MFD相关联的上游端口必须在每个PTM上下文刷新期间发出单个PTM对话框。 MFD内的PTM请求者使用此单个设备范围的PTM对话框维护其各自的PTM上下文。从一个PTM对话框中刷新多个PTM上下文的机制是实现特定的。

相关问题

With the rapid development of China's economy, the per capita share of cars has rapidly increased, bringing great convenience to people's lives. However, with it came a huge number of traffic accidents. A statistical data from Europe shows that if a warning can be issued to drivers 0.5 seconds before an accident occurs, 70% of traffic accidents can be avoided. Therefore, it is particularly important to promptly remind drivers of potential dangers to prevent traffic accidents from occurring. The purpose of this question is to construct a machine vision based driving assistance system based on machine vision, providing driving assistance for drivers during daytime driving. The main function of the system is to achieve visual recognition of pedestrians and traffic signs, estimate the distance from the vehicle in front, and issue a warning to the driver when needed. This driving assistance system can effectively reduce the probability of traffic accidents and ensure the safety of drivers' lives and property. The main research content of this article includes the following aspects: 1. Implement object detection based on the YOLOv5 model. Conduct research on convolutional neural networks and YOLOv5 algorithm, and develop an object detection algorithm based on YOLO5. Detect the algorithm through road images, and analyze the target detection algorithm based on the data returned after training. 2. Estimate the distance from the front vehicle based on a monocular camera. Study the principle of estimating distance with a monocular camera, combined with parameters fed back by object detection algorithms, to achieve distance estimation for vehicles ahead. Finally, the distance estimation function was tested and the error in the system's distance estimation was analyzed. 3. Design and implementation of a driving assistance system. Based on the results of two parts: target detection and distance estimation, an intelligent driving assistance system is constructed. The system is tested through actual road images, and the operational effectiveness of the intelligent driving assistance system is analyzed. Finally, the driving assistance system is analyzed and summarized.

我检查了一下，这段文字没有明显的语法或拼写错误。不过，有一些翻译上的问题。例如，第二句话应该是“However, this has also led to a huge number of traffic accidents.” 而不是“However, with it came a huge number of traffic accidents.” 此外，在第三句话中，“A statistical data”应该为“A statistical datum”或“A statistical data point”。在第四句话中，“promptly remind drivers of potential dangers”应该为“promptly warn drivers of potential dangers”。总的来说，这段文字需要一些润色和修改才能更加准确和流畅。

代码_ucaKey[0] = ((u32_Key >> 24) & 0xFF);报错This message is issued when a constant expression of essentially signed type with a non-negative value has been used as an operand of a bitwise operator.怎么修改

这个问题通常出现在使用有符号整数类型时，将其转换为无符号整数类型并进行位运算时。对于这种情况，可以使用类型转换来解决问题。例如，可以将有符号整数转换为无符号整数，然后再进行位运算，如下所示：

ucaKey[0] = static_cast<unsigned char>((u32_Key >> 24) & 0xFF);

在这里，使用了 static_cast 进行类型转换，将有符号整数转换为无符号整数类型，以避免出现上述问题。