Motherboard and control method thereof

A motherboard includes a south-bridge chipset, a north-bridge chipset and a central processor unit (CPU). The south-bridge chipset generates at least control-setting data. The north-bridge chipset has a reset register for controlling the north-bridge chipset to generate a reset signal and a control-set resister for storing the control-setting data generated by the south-bridge chipset. The CPU has a plurality of configuration parameters. The configuration parameters of the CPU are reset in accordance with the reset signal, and the control-setting data is written into the CPU by the north-bridge chipset to set one of the configuration parameters of the CPU.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a motherboard and the control method thereof. In particular, the invention relates to a motherboard that can reset the CPU and the control method thereof.

2. Related Art

The central processing units (CPU) of computers have evolved from the 8086, 80286, 80386, and 80486 series in the early days to the modern Pentium 4 series, rendering more and better functions, computing speeds, and processing efficiency. With powerful functions and increasing data processing amount, the system has to perform more actions during the power on procedure to ensure the proper functioning of the CPU.

Take the Pentium 4 series CPU as an example. The motherboard has to send out a CPU_reset signal to the CPU during the boot power on self test (POST) in order to reset the CPU and to set the frequency multiplier of the CPU. The frequency multiplier refers to the ratio between the frequencies of the CPU and the system bus. When the external frequency is fixed, increasing the frequency multiplier will increase the main frequency of the CPU.

With reference toFIG. 1, the conventional way of resetting the CPU is achieved by an external reset from a south-bridge chipset11. When the south-bridge chipset11performs the reset, a peripheral connecting interface reset (PCI_reset) signal S1is generated. The PCI_reset signal is transmitted to a north-bridge chipset12to reset the north-bridge chipset12. When north-bridge chipset12performs the reset, a CPU reset (CPU_reset) signal S2is transmitted to the CPU13to reset the CPU13.

However, aside from resetting the CPU13in the above-mentioned method, the north-bridge chipset12and the south-bridge chipset11are reset too. Therefore, it takes extra time to rewrite the data in the north-bridge chipset12and the south-bridge chipset11.

Consequently, how to avoid writing the data required by the north-bridge chipset and the south-bridge chipset when resetting the CPU for saving time is currently an important issue.

SUMMARY OF THE INVENTION

In view of the foregoing, the invention is to provide a motherboard having a north-bridge chipset for automatically generating a rest signal to reset the CPU and the control method thereof.

To achieve the above, a motherboard of the invention includes a south-bridge chipset, a north-bridge chipset, and a CPU. The south-bridge chipset generates at least control-setting data. The north-bridge chipset has a reset register and a control-setting register. The reset register is used to control the north-bridge chipset to generate a rest signal, and the control-setting register is used to store the control-setting data generated by the south-bridge chipset. The CPU has a plurality of configuration parameters and resets these configuration parameters in accordance with the reset signal. The north-bridge chipset writes the control setting-data into the CPU for setting at least one of the configuration parameters.

In addition, the invention also discloses a motherboard control method applied in a motherboard including a north-bridge chipset with a reset register and a CPU with a plurality of configuration parameters. The control method includes the steps of: generating a reset signal according to a value of the reset register by the north-bridge chipset, and resetting the configuration parameters by the CPU according to the reset signal.

Furthermore, the invention also discloses a method for setting a CPU of a motherboard. The motherboard further comprises a north-bridge chipset having a reset register, and the CPU has a plurality of configuration parameters. The method comprises the steps of: generating a reset signal by the north-bridge chipset in accordance with a value of the reset register, and resetting the configuration parameters by the CPU in accordance with the reset signal.

As mentioned above, the invention provides a reset register in the north-bridge chipset. The north-bridge chipset generates a reset signal in accordance with the contents of the reset register. The CPU resets the configuration parameters of the CPU according to the reset signal, without resetting the north-bridge chipset and the south-bridge chipset at the same time.

DETAILED DESCRIPTION OF THE INVENTION

As shown inFIG. 2, a motherboard2according to a preferred embodiment of the invention has a north-bridge chipset21, a CPU22, and a south-bridge chipset23. To make the invention more comprehensive, the detailed features of the motherboard2will be described as follows.

The north-bridge chipset21has a reset register211and a control-setting register212. The reset register211controls the north-bridge chipset21to generate a reset signal S3. In this embodiment, the north-bridge chipset21generates the reset signal S3when a value of the reset register211is enabled.

The south-bridge chipset23outputs at least one strapping value/strapping setting D1to the north-bridge chipset21and stores the strapping value/strapping setting D1in the control-setting register212of the north-bridge chipset21. In this embodiment, the north-bridge chipset21writes the strapping value/strapping setting D3, which is a part of the strapping value/strapping setting D1, into the CPU22for setting at least one of the configuration parameters221of the CPU22. Besides, the strapping value/strapping setting D1can contain at least one of memory module controller control-setting data and memory module control-setting data. Moreover, the memory module control-setting data includes at least one of frequency data and timing data for setting the frequency or clock of a memory module. Furthermore, the control-setting register212may also store the setting data of other units in the motherboard2.

With reference toFIG. 3showing a schematic partial view of the motherboard2, the north-bridge chipset21also includes a default control-setting register213to store at least a default strapping value/default strapping setting D2. The north-bridge chipset21writes the default strapping value/default strapping setting D2into the CPU22, setting at least one of the configuration parameters221of the CPU22. Depending upon the system requirement, it sets the configuration parameters for the system to return to its default state.

To make the invention more comprehensive, a motherboard control method according to a preferred embodiment of the invention will be described with reference toFIG. 4in view ofFIG. 2.

In step P11, the north-bridge chipset21generates a reset signal S3according to the value of the reset register211. In this embodiment, the north-bridge chipset21generates the reset signal S3when the value of the reset register211is enabled. What means enabled depends upon the choice of the designer and is not restricted here.

In step P12, the CPU22resets the configuration parameters221of the CPU22in accordance with the reset signal S3.

Therefore, the configuration parameters221of the CPU22are reset by the reset signal S3automatically sent out by the north-bridge chipset21. This avoids resetting the north-bridge chipset21and the south-bridge chipset23at the same time when the CPU22is reset.

With reference toFIGS. 5 and 2, the motherboard2further includes a south-bridge chipset23, and the motherboard control method may further include the following steps.

In step P21, at least one strapping value/strapping setting D1is output from the south-bridge chipset23to the north-bridge chipset21.

In step P22, the north-bridge chipset21stores the strapping value/strapping setting D1output from the south-bridge chipset23in a control-setting register212.

In step P23, the north-bridge chipset21writes the strapping value/strapping setting D3into the CPU22for setting at least one of the configuration parameters221. In this embodiment, the north-bridge chipset21writes the strapping value/strapping setting D3into the CPU22for setting the configuration parameters221only after the north-bridge chipset21sends out the reset signal S3to the CPU22and the CPU22resets the configuration parameters221.

The invention further discloses a method for setting a CPU of a motherboard. The motherboard further comprises a north-bridge chipset having a reset register, and the CPU has a plurality of configuration parameters. The method for setting a CPU includes the following steps. First, a reset signal is generated by the north-bridge chipset in accordance with a value of the reset register. Then, the configuration parameters are reset by the CPU in accordance with the reset signal. The method for setting a CPU of a motherboard is similar to the motherboard control method of the previous embodiment, so the detailed descriptions are omitted for concise purpose.

In summary, the invention adds a reset register to the north-bridge chipset. The north-bridge chipset generates a reset signal in accordance with the value of the reset register. The CPU resets the configuration parameters thereof according to the reset signal without resetting the north-bridge chipset and the south-bridge chipset at the same time. Moreover, a control-setting register is included in the north-bridge chipset to store the strapping value/strapping setting output from the south-bridge chipset. After the CPU is reset, the north-bridge chipset writes the strapping value/strapping setting into the CPU and sets the configuration parameters according to the system requirements.