JP2003198666A - Communication terminal unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the downloading time of software in the course of manufacturing a communication terminal unit. <P>SOLUTION: A switch 24 is provided in parallel with a second resistor 24 provided for protecting a CPU 2. At the time of downloading the software in the course of manufacturing the communication terminal unit, a first special command is first issued from a PC connected to the terminal unit through a cable. Upon receiving the command, an output port 14 turns on the switch 24 by outputting a first control signal. When the switch 24 is turned on, the signals of received data are supplied to a UART 12 through the switch 24 without passing through a second resistor 23. When the downloading of the software ends, a second special command is issued from the PC. Upon receiving the command, the output port 14 turns off the switch 24 by outputting a second control signal. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a data receiving circuit for receiving data transferred from another communication device such as a mobile phone, and a resistor for protecting the central processing unit from overvoltage. Related communication terminals.

[0002]

2. Description of the Related Art Conventionally, mobile phones such as so-called mobile phones and simple mobile phones (PHS; Personal Handyphone System (registered trademark)) have been proposed.

As shown in FIG. 6, the mobile phone 100 is
Central processing unit (hereafter, CPU)
Called. ) 101, terminal 102, SRAM (Stat
icRandom Access Memory) 103 and flash ROM
A (Read Only Memory) 104 and a liquid crystal screen 105 are provided.

The CPU 101 includes a CPU core 110, a memory controller 111, and a UART (Universal Alignment).
A equipped with chronous receiver transmitter (112)
SIC (Application Specific Integrated Circuit)
And 113.

The CPU core 110 controls the liquid crystal screen 105, the memory controller 111, an input unit (not shown) and the like.

The memory controller 111 is the SRAM 1
03, managing the input and output of data to and from the flash ROM 104.

The UART 112 converts serial data transferred from another communication device connected to the mobile phone 100 via a cable into parallel data, and
It is an interface for converting data to be transmitted to another communication device from parallel data to serial data. UA
The RT 112 has 16 signal lines, and for example,
TX serial line 114 for receiving data supplied from a communication device connected via a cable, R for transmitting data to the communication device connected via a cable
It has an X serial line.

A plug of a cable for connecting the mobile phone 1 to another communication device is inserted into the terminal 102. The mobile phone 100 can be connected to another communication device such as a personal computer (hereinafter referred to as a PC) via the cable.

The SRAM 103 stores data. For example, the SRAM 103 temporarily stores the data received by the mobile phone 100 via the network.

The flash ROM 104 stores the program code.

In the portable telephone 100 described above, when it is connected to another communication device via a cable to receive data, the data is received via the TX serial line 114.

As shown in FIG. 7, the TX serial line 114 includes a diode 120, a first resistor 121, a power supply 122, and a second resistor 123.

In the TX serial line 114, the data signal received by the mobile phone 100 is first transmitted to the terminal 102.
To the diode 120. Diode 120
When the signal supplied to is at high level, the diode 120 is turned off and the power supply 122 supplies the UART.
Current is supplied to 112. On the other hand, when the signal supplied to the diode 120 is at the low level, the diode 120 is turned on, and the power supply 122 turns on the UART 11.
2 is supplied with current, but the diode 120
A small amount of current is supplied as compared with the case of FF. That is, when the signal supplied to the diode 120 is at a high level, a high level voltage is applied to the CPU 101, and when the signal supplied to the diode 120 is at a low level, a low level voltage is applied to the CPU 101.

That is, when the mobile phone 100 receives data via the TX serial line 114, C
Voltage is applied to the PU 101. Mobile phone 100 is CP
When an overvoltage is applied to U101, each circuit in the CPU 101 is destroyed.

Therefore, in the portable telephone 100, when the C receives data via the TX serial line 114, the C
A diode 120 and a second resistor 123 are provided in the TX serial line 114 in order to prevent an overvoltage from being applied to the PU 101.

When manufacturing the mobile phone 100 described above, first, the CPU 101, the terminal 102, and the SRAM.
The respective parts such as 103 and the flash ROM 104 are manufactured and housed in a housing.

Then, software for adding functions such as an address book and a clock is downloaded to the mobile phone 100.

When downloading software to the mobile phone 100, first, the mobile phone 1 with the power turned off.
The plug of the cable is inserted into the terminal 102 of 00 and is connected to the PC having the data to be downloaded to the mobile phone 100 through the cable.

Next, the PC issues a special command for starting the software download and transfers it to the mobile phone 100. The mobile phone 100 enters the loader mode in which the software is downloaded by receiving the special command.

Next, the PC transfers the data to the mobile phone 100. The data transferred from the PC is first transmitted to the UART 112 via the TX serial line 114. The UART 112 converts the received serial data into parallel data.

The converted parallel data is sent to the SRAM 103 under the control of the memory controller 111.
Is written to. Finally, the data written in the SRAM 103 is read out under the control of the memory controller 111 and written in the flash ROM 104.

[0022]

By the way, when the mobile phone 100 is manufactured, it is required that the manufacturing time is short. Since the manufacturing time of the mobile phone 100 is shortened, the manufacturing operation rate is improved and the work efficiency can be improved.

As a means for reducing the manufacturing time of the mobile phone 100, it is possible to reduce the time required for downloading the software. The time required to download the software is the time required to transfer the data from the PC to the mobile phone 100, and the transferred data to the SRAM 10
3 is the total time of writing to the flash ROM 104 after writing to 3, and it is considered that the time for transferring data from the PC to the mobile phone 100 can be shortened in order to shorten the time required for downloading the software.

However, in the mobile phone 100, the T
When data is received via the X serial line 114, as shown in FIG. 8, it takes 5.5 μs until the received data signal rises to a high level, and then it falls to a low level. It takes 3.0 μs. In FIG. 8, the horizontal axis represents time and the vertical axis represents voltage. In FIG. 8, the waveform indicated by D shows the waveform of the signal passing through the position indicated by D in FIG. 7, and the waveform indicated by E shows the waveform of the signal passing through the position indicated by E in FIG. The waveform indicated by F is the waveform passing through the position indicated by F in FIG. Furthermore, in the mobile phone 100, when the voltage becomes xV (where x> 0), it is recognized as a high level.

The data transfer rate is determined by the reciprocal of the data rise time or the data fall time.
You can raise it to equal a small number. The reciprocal of the rise time and the reciprocal of the fall time of the signal received when the software is downloaded to the mobile phone 100 are as shown below.

Reciprocal of rise time: 1 / (5.5 × 1)
0 ^-6 s) ≒ 180000bps fall time of ^{reciprocal: 1 / (3.0 × 10 -6} s) ≒
330,000 bps That is, the data transfer speed when downloading software to the mobile phone 100 is about 180 kb.
ps or less.

The present invention has been proposed in view of such a conventional situation, and provides a communication terminal device capable of increasing the transfer rate of data from another communication device connected by a cable. The purpose is to

[0028]

A communication terminal device to which the present invention is applied includes a central processing unit in a data receiving circuit for receiving data transferred via another cable from another communication device connected by the cable. A communication terminal device provided with a resistor for protecting against overvoltage is characterized by comprising a switch connected in parallel to the resistor and a control means for controlling the switch.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

As shown in FIG. 1, a mobile phone 1 to which the present invention is applied includes a CPU 2, a terminal 3, an SRAM 4, a flash ROM 5 and a liquid crystal screen 6. CPU
2, the terminal 3, the SRAM 4, the flash ROM 5, and the liquid crystal screen 6 are housed in a casing (not shown).

The CPU 2 includes a CPU core 10, a memory controller 11, and a UART (Universal Asynchronous).
ASIC (App with Receiver Transmitter) 12
lication Specific Integrated Circuit) 13.

The CPU core 10 controls the liquid crystal screen 6, the memory controller 11, an input unit (not shown) and the like.
Further, the CPU core 10 includes an output port 14 as shown in FIG. Details of the output port 14 will be described later.

The memory controller 11 includes the SRAM 4,
It manages the input and output of data to and from the flash ROM 5. The memory controller 11 is connected to the SRAM 4, the flash ROM 5, and the liquid crystal screen 6 via an address bus and a data bus.

The UART 12 converts serial data transferred from another communication device connected via a cable having a plug inserted into the terminal 3 into parallel data, and converts data to be transmitted to another communication device into parallel data. Is an interface to convert from to serial data. The UART 12 transmits / receives data asynchronously without using a communication clock.

The UART 12 includes 16 signal lines such as a TX serial line 16 for receiving data from a communication device connected via a cable and an RX serial line for transmitting data to the communication device connected via a cable. have. The 16 signal lines provided in the UART 12 are connected to the terminal 3, respectively.

A cable plug is inserted into the terminal 3. The mobile phone 1 can be connected to another communication device such as a personal computer (hereinafter referred to as a PC) via a cable having a plug inserted in the terminal 3. By connecting the mobile phone 1 to another communication device,
For example, another communication device can be connected to the network.

The SRAM 4 stores data. SRA
The M4 temporarily stores, for example, data received by the mobile phone 1 via the network.

The flash ROM 5 stores data. For example, the data temporarily stored in the SRAM 4 is read by the memory controller 11 and then stored in the flash ROM 5.

The TX provided in the UART 12 will be described below.
The serial line 16 will be described in detail with reference to FIG. In FIG. 2, signal lines other than the TX serial line 16 are omitted.

The TX serial line 16 is a receiving circuit for receiving data from a communication device connected to the terminal 3 via a cable having a plug inserted therein.

The TX serial line 16 is connected to the diode 2
0 and 10kΩ first resistor 21 and 2.5V power supply 2
2, a second resistor 23 of 10 kΩ, and a switch 24.

In the TX serial line 16, UART1
2, the diode 20, and the second resistor 23 are connected in series with each other, and the switch 24 is connected in parallel with the second resistor 23. In the TX serial line 16, the diode 20 and the second resistor 23 are connected to the UART1.
The second resistor 23 and the diode 20 are arranged in this order from the second side. In the mobile phone 1, by disposing the second resistor 23 and the diode 20 in the TX serial line 16, it is possible to prevent an overvoltage from being applied to the CPU 2.

In the TX serial line 16, the data signal received by the mobile phone 1 is first supplied from the terminal 3 to the diode 20. When the signal supplied to the diode 20 is at high level, the diode 20
It becomes FF, and current is supplied from the power supply 22 to the UART 12. On the other hand, when the signal supplied to the diode 20 is low level, the diode 20 is turned on,
Although a current is supplied from the power supply 22 to the UART 12, a small amount of current is supplied as compared to when the diode 20 is OFF. That is, when the signal supplied to the diode 20 is at a high level, a high level voltage is applied to the CPU 2, and when the signal supplied to the diode 20 is at a low level, a low level voltage is applied to the CPU 2.

The switch 24 is turned on or off according to the control signal output from the output port 14.
By turning on the switch 24, the second resistor 23 can be short-circuited, and the received data is transmitted to the UART 12 without passing through the second resistor 23. Further, when the switch 24 is OFF, the received data passes through the second resistor 23 and the UART1
2 is sent.

The output port 14 outputs a first control signal for turning on the switch 24 and a second control signal for turning off the switch 24. In this embodiment,
The first control signal is output when the mobile phone 1 receives the first special command issued by the PC connected to the mobile phone 1, and the second control signal is the second control signal.
It is output when the mobile phone 1 receives the second special command issued by the PC connected to the mobile phone 1. The first special command is issued from the PC when the loader mode in which the software is downloaded to the mobile phone 1 is set in the manufacturing process of the mobile phone 1, and the second special command is issued by the PC when the loader mode ends. Published by.

The first special command and the second special command are used in the manufacturing process of the mobile phone 1 and are not known to general users. That is, the mobile phone 1 is configured so that a general user cannot control the switch 24.

The mobile phone 1 described above is manufactured by the procedure described below.

First, the CPU 2, the terminal 3, the SRAM 4, the flash ROM 5 and the like are manufactured and housed in a housing.

Then, software for adding various functions such as an address book and a clock is downloaded to the mobile phone 1.

When the software is downloaded to the mobile phone 1, first, as shown in FIG. 3, the mobile phone 1 with the power turned off and the PC 30 for downloading data to the mobile phone 1 are connected via the cable 31. Connecting.

Next, as shown in FIG. 4, the PC 30 issues a first special command for starting the download of the software to the mobile phone 1 and transfers it to the mobile phone 1 (ST1). Upon receiving the first special command, the mobile phone 1 enters the loader mode in which the software is downloaded. In addition, the mobile phone 1 receives the first special command, so that the output port 14 becomes the first
The control signal is output, and the switch 24 is turned on (ST
2).

Next, the PC 30 transfers the data to the mobile phone 1 (ST3). The data transmitted from the PC 30 is first transmitted via the TX serial line 16 to the UA.
Sent to RT12. Switch 24 in ST3
Is ON, the current output from the power supply 22 does not pass through the second resistor 23 but passes through the switch 24, and U
It is supplied to the ART 12.

When the software is downloaded to the mobile phone 1 in the manufacturing process, the current supplied to the UART 12 is fixed, and even if the current supplied from the power supply 22 does not pass through the second resistor 23, the CP
It is known that no overvoltage is applied to U2.
Therefore, in the mobile phone 1, when the software is downloaded in the manufacturing process, the switch 24 is turned on so that the current output from the power supply 22 can be supplied to the UART 12 without passing through the second resistor 23. It will be possible.

Next, the UART 12 converts the received data from serial data into parallel data.

Then, the parallel data converted by the UART 12 is S-converted under the control of the memory controller 11.
It is written in the RAM 4.

The data written in the SRAM 4 is read out under the control of the memory controller 11 and written in the flash ROM 5.

When the data transfer and the writing to the flash ROM 5 are completed (ST4), the PC 30 issues a second special command for ending the software download and transfers it to the mobile phone 1 (ST5). When the mobile phone 1 receives the second special command, the loader mode ends. In addition, the mobile phone 1 receives the second special command, and the output port 14 receives the second special command.
Is output, and the switch 24 is turned off (S
T6). The mobile phone 1 is shipped with the switch 24 turned off.

In the mobile phone 1, for example, when the software to be downloaded is changed,
When a large voltage is applied to the CPU 2 when downloading the software, it is possible to avoid overvoltage on the CPU 2 by turning off the switch 24 and downloading the software.

When the software is downloaded to the mobile phone 1 by the method described above, the waveform of the signal received by the mobile phone 1 becomes as shown in FIG. Figure 5
In the figure, the horizontal axis represents time and the vertical axis represents voltage. Further, in FIG. 5, the waveform indicated by A indicates the waveform of the signal passing through A in FIG. 2, the waveform indicated by B indicates the waveform of the signal passing through the position indicated by B in FIG. 2, and C The waveform indicated by is the waveform of a signal passing through the position indicated by C in FIG. That is, the waveform indicated by C in FIG. 2 indicates the voltage applied to the CPU 2. In this embodiment, when the voltage becomes xV (where x> 0), it is recognized as a high level.

As shown in FIG. 5, when the switch 24 is turned on and the software is downloaded to the mobile phone 1, the rise time of the signal supplied to the UART 12 is about 3.5 μs, and the fall time of the signal is about 0 μs.
s.

The data transfer rate can be increased until it becomes equal to the smaller of the reciprocal of the signal rise time and the reciprocal of the signal fall time. The reciprocal of the rise time and the reciprocal of the fall time of the signal received when the switch 24 is turned on and the software is downloaded to the mobile phone 1 are as follows.

Reciprocal of rise time: 1 / (3.5 × 1
0 ⁻⁶ s) ≈285000 bps Reciprocal of fall time: 1/0 = ∞ That is, when the switch 24 is turned on and software is downloaded to the mobile phone 1, the data transfer rate can be increased to 285 kbps.

Therefore, the mobile phone 1 is equipped with the switch 2
By turning on 4 and downloading the software, it is possible to increase the data transfer rate about twice as much as that of the mobile phone without the switch 24.

As described above, the portable telephone 1 to which the present invention is applied has the switch 24 provided in parallel with the second resistor 23 and the first control signal and the switch 24 for turning on the switch 24. And an output port 14 for outputting a second control signal for turning off the switch. When downloading the software in the manufacturing process, the mobile phone 1 first enters the loader mode by the first special command transmitted from the connected PC 30, and the output port 14 outputs the first control signal to switch. 24
Is turned on. Then, the data is transferred from the PC 30 to the mobile phone 1. The data transferred to the mobile phone 1 passes through the TX serial line 16 and is supplied to the UART 12. When the signal passed through the TX serial line 16 is supplied to the UART 12, it passes through the switch 24 without passing through the second resistor 23.

Therefore, in the mobile phone 1 to which the present invention is applied, by lowering the resistance applied to the signal supplied to the UART 12, the rise time of the signal can be shortened and the data transfer speed can be increased. It is possible to shorten the time to download.

That is, the mobile phone 1 to which the present invention is applied.
Can be manufactured in a short time, and the manufacturing operation rate and the production efficiency are good.

Generally, in a mobile phone, it is necessary to set the data transfer rate for downloading and the data transfer rate for uploading to be the same. Therefore, in the mobile phone 1 to which the present invention is applied, it is possible to increase the transfer rate of data at the time of uploading. For example, when debugging or analyzing software written in the mobile phone 1, data transfer is possible. It is possible to shorten the time to upload.

In the present embodiment, an example in which the present invention is applied to a mobile phone has been described. However, the present invention is not limited to a mobile phone, but can receive data for receiving data transferred from another communication device. Any communication terminal device can be applied as long as the circuit is provided with a resistor for preventing a high voltage from being applied to the central processing unit.

[0069]

The communication terminal device according to the present invention comprises a switch provided in parallel with a resistor for protecting the central processing unit, and a control means for controlling the switch.
In the communication terminal device according to the present invention, when software is downloaded from another communication device connected by a cable in the manufacturing process, first, the switch is turned on according to the control by the control means, and then the other communication device is connected. Data is transferred. The signal of the transferred data passes through the receiving circuit and is supplied to the central processing unit. When fed to the central processing unit, the signal passes through the switch rather than through the resistor.

Therefore, in the communication terminal device according to the present invention, by lowering the resistance applied to the signal supplied to the central processing unit, the rise time of the signal can be shortened and the data transfer speed can be increased. Therefore, it becomes possible to shorten the time for downloading the software.

That is, the communication terminal device according to the present invention is
It is possible to manufacture in a short time, and the manufacturing operation rate and the production efficiency are good.

[Brief description of drawings]

FIG. 1 is a block diagram showing a mobile phone to which the present invention is applied.

FIG. 2 is a circuit diagram of a TX serial line of the mobile phone.

FIG. 3 is a schematic diagram showing a state in which the mobile phone and a PC are connected.

FIG. 4 is a flowchart when downloading software to the mobile phone.

FIG. 5 is a diagram showing a waveform of a signal at a position indicated by C in FIG. 2 when software is downloaded with the switch turned on in the mobile phone.

FIG. 6 is a block diagram showing a conventional mobile phone.

FIG. 7 is a circuit diagram of a TX serial line of the mobile phone.

8 is a diagram showing a waveform of a signal at a position indicated by F in FIG. 7 when software is downloaded in the mobile phone.

[Explanation of symbols]

2 CPU, 3 terminals, 10 CPU core, 11 memory controller, 12 UART, 13 ASIC, 14
Output port, 16 TX serial line, 20 diode, 21 first resistance, 22 power supply, 23 second resistance, 24 switch

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiko Fujinaka             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Atsuhisa Akagi             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation (72) Inventor Genji Tonozaki             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F-term (reference) 5K027 AA11 BB01 GG01

Claims (2)

[Claims] 1. A communication terminal device, wherein a data receiving circuit for receiving data transferred via another cable from another communication device connected to the cable is provided with a resistor for protecting the central processing unit from overvoltage. A communication terminal device, comprising: a switch connected in parallel to the resistor; and a control unit that controls the switch. 2. The control means turns on the switch based on a first special command issued by the other communication device, and based on a second special command issued by the other communication device. The communication terminal device according to claim 1, wherein the switch is turned off.