1. Introduction With the continuous development of electronic technology, automotive electronics technology has also developed rapidly. The number of various electronic control units in automobiles is constantly increasing, and the number of connecting wires is significantly increasing. Therefore, improving the reliability of communication between control units and reducing wire costs have become urgent problems to be solved. In the 1980s, Bosch, a German company renowned for its research and production of automotive electronic products, developed the CAN bus protocol to address this problem. This multi-master network protocol is based on a non-destructive arbitration mechanism, enabling the bus to access messages with the highest priority without any delay. As a standard in-vehicle network technology, CAN plays a bridging and linking role in the process of automotive networking applications, raising the integration and collection of urban bus information to a new level. 2. Overview of Urban Bus Information Integration Control System The urban bus information integration control system is based on automotive network control technology. From the perspective of the controlled object, the urban bus information integration control system can be divided into powertrain electronic systems, safety and chassis electronic systems, and body electronic systems. The control system block diagram is shown in Figure 1. Figure 1. Block diagram of information integration and control for urban buses. The powertrain electronic system consists of EEC (engine electronic control), ECT (electronic control transmission), and electronic power steering. The information displayed on the instrument panel comes from the powertrain electronic system, centrally displaying driving information on the instrument panel, showing information related to the bus's operation, such as vehicle speed, engine speed, mileage, fuel level, coolant temperature, and fault alarms. The safety and chassis electronic system includes ABS (anti-lock brake system), ASR (anti-slip retractor), SAB (safety air bag), CCS (cruise control system), retarder, and suspension system control. Signal control is related to the components of the body electronic system, controlling automatic windows, lights, air conditioning, wipers, audio-visual equipment, electronic monitors, electric rearview mirrors, and sunroof. 3 System Structure Design 3.1 Information Integration Control System The information integration control system is the core of the entire urban bus information integration control system. Its task is to comprehensively apply automotive electronic control technology, in-vehicle network technology, and intelligent control technology to achieve information sharing and real-time control among the various ECUs of the urban bus, thereby improving the overall safety and comfort of the urban bus and reducing reliance on driver skills. From the perspective of information exchange, the urban bus information integration control system is divided into a powertrain control subsystem and a body control subsystem. The powertrain control subsystem includes the engine control system and the chassis control system. The body control subsystem includes the body electronic system and the instrument panel control system. Information exchange within the powertrain control subsystem is frequent, requiring extremely high real-time control information; while the real-time requirements for information exchange within the body control subsystem are relatively lower compared to the powertrain control subsystem. Information exchange also exists between the powertrain control subsystem and the body control subsystem. If a single-bus structure is adopted, i.e., all ECUs are connected to the same CAN bus, the superposition of information transmission between the two subsystems will inevitably increase the network load and reduce the real-time performance of the control information. We adopt a dual-bus architecture. The powertrain control subsystem uses a high-speed CAN bus with an information transmission rate of 500kb/s, while the body control subsystem uses a low-speed CAN bus with an information transmission rate of 100kb/s. Limited communication between the two is achieved through a gateway. The gateway is the core of the urban bus information integration control system and the foundation of integrated control. Its main function is to analyze and process various information, issue commands, and coordinate the operation of various control units and electrical equipment in the vehicle. The topology of the urban bus information integration control system is shown in Figure 2. Figure 2: Topology of the Urban Bus Information Integration Control System. 3.2 Gateway and Bus Interface The gateway uses the Philips LPC2101 microcontroller, an ARM7 TDMI-S CPU that supports real-time simulation, with 8kb and 32kb of embedded high-speed flash memory. The 128-bit wide memory interface and unique acceleration architecture enable 32-bit code to run at maximum clock speed. This improves the performance of critical functions in interrupt service routines and DSP algorithms by 30% compared to thumb mode. Applications with strict code size control can use the 16-bit thumb mode to reduce code size by more than 30% with minimal performance loss. It integrates two CAN controllers internally, with key features including: data transfer rates up to 1 MB/s on a single bus; 32-bit register and RAM access; CAN 2.0b compatibility; a global acceptance filter that recognizes all 11-bit and 9-bit RX flags; and full CAN-style automatic reception for selected standard flags. The CAN transceiver uses the Philips TJA1050 interface chip, which provides differential transmission performance for the bus and differential reception performance for the CAN controllers. The LPC2101 microcontroller is connected to both CAN buses via optocouplers and the high-speed CAN bus transceiver TJA1050. The connection methods for the two CAN buses are basically the same, and both CAN bus drivers use isolated DC/DC modules with separate power supplies. This not only achieves electrical isolation between the two CAN interfaces but also isolation between the gateway and the CAN bus. The gateway and bus structure is shown in Figure 3. Figure 3. Gateway and CAN bus interface structure. 4. System software design. The main function of the CAN/CAN gateway is to filter and forward data between two CAN network segments. Due to the real-time communication requirements in the urban bus information integration control system, the data storage and forwarding time must be minimized during software design. To achieve this, data reception uses IRQ. Since the data communication volume of the powertrain control subsystem is significantly higher than that of the body control subsystem, CAN1, which connects to the powertrain control subsystem, is given the highest priority, while CAN2, which connects to the body control subsystem, has the next highest priority. Interrupt service routines are also simplified to minimize system response time. Due to different transmission rates, data transmission between high-speed and low-speed CAN networks differs. When high-speed CAN network data is transmitted to low-speed CAN, a soft buffer is needed for temporary storage; when low-speed CAN network data is transmitted to high-speed CAN network, it can be transmitted directly. The overall process is shown in Figure 4. Figure 4. High-speed and low-speed CAN gateway communication process. 5. Conclusion. The CAN bus, with its high performance, high reliability, and unique design, is increasingly valued and is widely recognized as one of the most promising buses in automotive control networks. This paper presents a design scheme for an integrated information control network for urban buses with high- and low-speed CAN networks, and introduces the hardware and software design of the LPC2101 microcontroller as a high- and low-speed gateway in this CAN network. The automotive computer control unit can share all information and resources through the CAN bus, achieving the goals of simplifying wiring, reducing the number of sensors, avoiding duplicate control functions, improving system reliability and maintainability, reducing costs, and better matching and coordinating various control systems.