CN100485652C - Multiple interfaces program loading apparatus for mobile terminal - Google Patents

Abstract

The invention provides a multi-port program downloading device for a mobile terminal, including a USB expansion circuit connected to a computer USB port, a conversion circuit for converting USB signals into UART signals, and a switching power supply module with 220V input and 5V DC output , the switching power supply module supplies power to chips and mobile terminals after being processed by circuits such as filtering, voltage transformation, and voltage stabilization. The shortcomings of high cost and slow communication speed of the expansion scheme can be applied to high-speed multi-port program downloading of mobile terminals, improving production efficiency and reducing costs.

Description

Mobile terminal multi-port program downloading device

technical field

The present invention belongs to the technical field of communication and program download between different devices, more specifically, it relates to USB ports connecting multiple mobile terminals and computers, so as to realize simultaneous data transmission between multiple mobile terminals and a computer and program downloads.

Background technique

In the mobile terminal industry, when performing data transmission between computers and mobile terminals, the more commonly used technical method is to communicate between the COM port of the PC, that is, the serial communication port, and the UART port of the mobile terminal, especially in the mobile terminal. In the manufacturing mode of the current mobile terminal, the UART port of the mobile terminal is connected to the COM port of the PC for one-to-one data transmission and program download.

In order to meet the large-scale and fast communication required by the production or after-sales service of mobile terminals, a serial port expansion card is installed at one end of the computer to communicate with multiple mobile terminals at the same time through the expansion of the serial port. But the application of this one-to-many technical solution also has disadvantages. The first problem is that the cost is high and circuit design needs to be increased. Secondly, the communication speed of the serial port of the computer is slow, and it takes a long time to download data. Using the serial port of the computer makes this solution lack the space for communication speed improvement.

Contents of the invention

The purpose of the present invention is to solve the shortcomings of slow communication speed and high cost between the serial port of the computer and the serial port of the mobile terminal. The USB port of the computer is used to provide a device for inputting one-way computer USB differential signals and outputting eight-way UART signals. It enables one computer to communicate with eight mobile terminals at the same time, which can be widely used in mobile terminal PCB Test, software download, after-sales software upgrade and other applications. At the same time, because all chips supporting USB2.0 are used, the device can realize the The high-speed communication between computers, together with the software on the PC side, can adjust the communication rate according to the needs, and greatly improve the communication speed.

In order to achieve the above object, the present invention includes a USB expansion circuit connected to a computer USB port, a conversion circuit connected to the USB expansion circuit to convert USB signals into UART signals, and a switching power supply module with 220V input and 5V DC output.

The USB expansion circuit of this device is used to expand the USB port; the conversion circuit is used to realize the signal conversion between USB differential signal and UART; at the same time, it adopts a switching power supply module with 220V input and 5V DC voltage output, which is filtered, transformed and stabilized. After the circuit is processed, power is supplied to the chip and the mobile terminal to ensure normal communication between the mobile terminal and the computer.

The USB expansion circuit includes a USB port expansion chip, a crystal oscillator circuit connected to the USB port expansion chip, and a filter circuit to realize the functions of one USB differential signal input and four USB differential signal outputs. One pin of the USB port expansion chip is connected to the voltage of the USB port of the computer through a diode. It can use the USB power supply mode and be applied to devices with a driving current less than 500mA.

The conversion circuit includes a USB differential signal to UART signal chip, a crystal oscillator circuit connected to the USB differential signal to UART signal chip, a filter circuit, and an LED driver circuit to realize the functions of one USB differential signal input and two UART signal outputs. Setting the level of a pin of the USB differential signal to UART signal chip can change the reference level of the two UART output signals, and is applied to download devices that require different voltages and have a TTL logic interface.

The switching power supply module is a DC stabilized power supply, which can provide a maximum of 30W of 5V DC voltage output. After passing through the filter circuit, and then processed by the LDO voltage transformation and stabilization circuit, it can provide 4.1V and 5V adjustable voltages respectively Supply power to GSM and CDMA mobile terminals.

The present invention can be widely used in high-speed communication between various devices with TTL logic interface and computers, and is preferably used in the connection between mobile terminals and computers to download program data. This device can convert one USB differential signal of the computer into multiple UARTs Signals are connected to multiple mobile terminals at the same time, which meets the needs of large-scale downloads and high-speed communication in the production line and update software applications.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a block diagram of circuit principle of the present invention;

Fig. 2 is the circuit diagram of LDO voltage transformation and voltage stabilization in one embodiment of the present invention;

Fig. 3 is a USB expansion circuit diagram in an embodiment of the present invention;

Fig. 4 is a conversion circuit diagram of USB differential signal to UART signal in one embodiment of the present invention.

Detailed ways

As shown in Figure 1, it is a block diagram of the principle of a multi-port program downloading device for a mobile terminal. Its specific working principle is as follows: through the switching power supply module 1, the 220V AC power is converted into 5V DC voltage, and the voltage is output after being transformed and stabilized by the LDO. The voltage of 3.3V supplies power to the USB expansion circuit 2, and the USB expansion circuit communicates with the four-way USB differential signal to UART signal conversion circuit 3 through the relevant pins, and the relevant pins of the USB to UART chip are connected to the DA/DB serial port, And communicate with the mobile terminal MS through the mobile terminal data line.

At the same time, one of the switching power supply module 1 outputs 5V voltage through a switch, and one path is directly connected to DA, and supplies 5V DC voltage to the CDMA mobile terminal through the mobile terminal data line, and the other path outputs 4.1V after being transformed and stabilized by an LDO. The voltage is supplied to DA, and the DC voltage of 4.1V is supplied to the GSM mobile terminal through the data line;

The 5V DC voltage output by the other channel of the switching power supply module 1 passes through a switch, and one channel is directly connected to the DB, and supplies a 5V DC voltage to the CDMA mobile terminal through the data line, and the other channel outputs a 4.1V voltage after being transformed and stabilized by an LDO Supply DB, and supply 4.1V DC voltage to the GSM mobile terminal through the data line. The reason why two switches are used to control the output of the DC voltage is that there are very few suitable switching devices with a current limit of 6A, so two switches with a current limit of 3A are used; the second is that it is easy to debug because of the two switches. and maintenance.

As shown in Figure 2, it is the circuit diagram of LDO voltage transformation and stabilization. Its specific working principle is as follows: the input voltage of U2 is 5V, and the 5V voltage comes from switching power supply module 1, which is filtered by the combination of capacitors, and then input to the chip through switch S1 U2, at the same time, connect the enable terminal of chip U2 to high level, let the chip U2 enter the working state, after the internal voltage transformation and stabilization of the chip U2, by adjusting the values of R19 and R20, different output voltages can be obtained. To supply power to the mobile terminal, the output voltage is set to 4.1V considering the voltage drop of the PCB circuit board and the data line of the mobile terminal.

Connect a common-cathode two-color LED lamp L1 behind the switch S1, so that you can distinguish whether the supplied voltage is 5V DC voltage or 4.1V DC voltage. The input voltage of U4 is also 5V. After filtering with a capacitor at the input end, the output The terminal outputs a constant 3.3V DC voltage to supply power to the USB port expansion chip and the USB to UART chip.

As shown in Figure 3, it is a circuit diagram of a USB HUB. Its specific working principle is as follows: first, the USB port expands the working voltage of the chip 2-1, which is obtained by connecting an external 3.3V DC voltage. A diode D1 is connected to the voltage of the USB port of the computer, so that when there is no external 5V DC voltage, the USB port expansion chip 2-1 is powered by the 5V voltage of the USB port after being transformed and stabilized by the LDO. This is just an alternative, after all, the maximum drive current of USB is only 500mA.

The second is the signal transmission of the USB port expansion chip 2-1. The differential signal at the USB port of the computer is filtered by a capacitor and then input to the USB port expansion chip 2-1. After pull-down and capacitor filtering, the output is sent to the USB to UART chip 3-1; then the crystal oscillator circuit uses a 12MHz crystal oscillator and enters the chip after a matching circuit to provide a reference clock for the chip; finally, the peripheral circuit of the chip, according to the work of the chip According to the characteristics and our actual needs, the corresponding pins of the chip are processed to make the chip work in the required state.

As shown in Figure 4, it is a conversion circuit diagram of USB differential signal to UART signal. Its specific working principle is as follows: First, the working voltage of chip 3-1 is obtained by connecting an external 5V DC voltage. Since this chip has strict requirements on the working voltage, multiple capacitors with different parameters are connected in parallel for strict filtering, and the VCCIO pin is connected to 3.3V, so that the high level of the output signal of chip 3-1 will be 3.3V V, if you connect VCCIO to other levels, you can change the high level value of the output signal; secondly, the signal transmission of chip 3-1, expand the four-way differential signal output by chip 2-1 from the USB port Among them, one channel is selected to be input to the USB to UART chip 3-1 after the filter capacitor and matching resistor, and then through the internal conversion of the chip 3-1, two channels of UART serial port signals are output, and according to the requirements of the signal level value received by the mobile terminal, Add drop-down resistors to the required pins such as 19, 21, 35 and 37 to ensure that the internal circuit of the mobile terminal will not be damaged during normal communication; then the crystal oscillator circuit uses a 6MHz crystal oscillator and is filtered by a capacitor Finally, input the chip to provide a reference clock for the chip; then the power supply circuit of the mobile terminal, we connect 5V and 4.1V DC voltages to the 4 pins and 9 pins of DA/DB respectively, so that the mobile terminal can be provided with 5V or With a DC voltage of 4.1V, the purpose of powering or charging mobile terminals on different platforms can be achieved by defining a corresponding connection method for the mobile terminal data line.

The last is the peripheral circuit of the chip. According to the working characteristics and actual needs of the chip, the corresponding pins of the chip need to be processed to make the chip work in the required state. At the same time, use pins 11, 12, 27, and 28 to supply power to the light-emitting diodes through an external 3.3V DC voltage and a current-limiting resistor. In this way, when the mobile terminal communicates with the computer, when one end is connected to the computer and the other end is connected to a plurality of mobile terminals, the multi-port program downloading device sends or receives a piece of data, the corresponding light-emitting diodes will flicker, which not only reflects the work of the device state, and facilitate debugging and maintenance.

Claims (6)

1. multiple interfaces program loading apparatus for mobile terminal, it is characterized in that comprising that the USB that is connected to the computer USB port expands circuit, and connection USB expands circuit, the USB differential signal transferred to the UART signal and output to the change-over circuit of UART interface, and switch power module, described switch power module input external communication civil power, output two-way dc constant voltage power supply, wherein one the road be connected to described expansion circuit and change-over circuit is used to provide operating voltage, another road is connected to described UART interface and is used for providing direct supply to portable terminal, and portable terminal is connected to the UART interface by data line.

2. multiple interfaces program loading apparatus for mobile terminal according to claim 1, it is characterized in that described USB expands circuit and comprises USB port expensive chip, the crystal oscillating circuit and the filtering circuit that are connected with the USB port expensive chip, described USB expands circuit and imports one road USB differential signal, exports four road USB differential signals.

3. multiple interfaces program loading apparatus for mobile terminal according to claim 2 is characterized in that pin of described USB port expensive chip links to each other with the voltage of the USB port of computer by a diode, can use the USB powering mode.

4. according to claim 2 or 3 described multiple interfaces program loading apparatus for mobile terminal, it is characterized in that described change-over circuit comprises that the USB differential signal changes the UART signal chip, change crystal oscillating circuit, filtering circuit, the led drive circuit that the UART signal chip is connected with the USB differential signal, described change-over circuit is imported one road USB differential signal, output two-way UART signal.

5. multiple interfaces program loading apparatus for mobile terminal according to claim 4, it is characterized in that described switch power module output two-way 5V dc constant voltage power supply, one tunnel wave circuit after filtration wherein, give described USB port expensive chip and described USB differential signal for 3.3V voltage after the processing of transformation mu balanced circuit and change the power supply of UART signal chip, another road is by a dual-colored LED lamp, the optional DC voltage of output 5V, 4.1V is given the portable terminal power supply of CDMA standard and GSM standard, the real-time display voltage pattern of dual-colored LED lamp respectively.

6. multiple interfaces program loading apparatus for mobile terminal according to claim 5 is characterized in that described being used for control the output of this power supply to another road 5V dc constant voltage power supply of portable terminal power supply by double switch, and every way switch current limliting is 3A.

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