CN105488004A - I2C line multiplexing control logic method under startup and shutdown states of server - Google Patents

The invention discloses an I2C line multiplexing control logic method under startup and shutdown states of a server. When a BMC (Baseboard Management Controller) cannot be started at an ultralow temperature, a temperature sensor of a mainboard is connected to a CPLD (Complex Programmable Logic Device) logic control device to sense a temperature of the mainboard, and determine whether a mainboard heating function needs to be performed, at this time, the CPLD is an I2C primary device and the temperature sensor is an I2C slave device; after successful booting, two groups of I2C buses of the BMC are switched to control the CPLD and the temperature sensor respectively through an I2C bus switch, and at this time, the BMC is the I2C primary device, and the CPLD and the temperature sensor are the I2C salve devices. According to the I2C line multiplexing control logic method under the startup and shutdown states of the server provided by the invention, under a shutdown state, the BMC and other control units manage a Thermal sensor and other I2C controllers, so that after starting up, other devices control the I2C controllers, thus the problem that computers are not started under a low temperature state can be solved.

A kind of I2C line sharing steering logic method under server on-off state

Technical field

The present invention relates to I2C circuit control technology field, be specifically related to a kind of I2C line sharing steering logic method under server on-off state.

Background technology

I2C bus supports any IC production run (NMOSCMOS, bipolarity).Two lines--serial data (SDA) and serial clock (SCL) line are being connected to transmission of information between the device of bus.Each device has a unique Address Recognition (no matter be microcontroller---MCU, lcd driver, storer or keyboard interface), and can as a transmitter or receiver (being determined by the function of device).Clearly, lcd driver is a receiver, and storer then both can receive and can send data.Except transmitter and receiver, device also can be counted as main frame or from machine when performing data transmission.Main frame is that the data of initialization bus are transmitted and produce the device of the clock signal allowing transmission.Now, any addressed device is all considered to from machine.

Bus characteristic:

1, two bus lines are only required: a serial data line SDA, a serial time clock line SCL;

2, each device being connected to bus can be software set address by unique address and the simple main frame existed/from office always, and main frame can as main frame transmitter or host receiver;

3, it is real many host buses, if the initialization simultaneously of two or more main frames, data transmission can be destroyed by collision detection and arbitration prevent data;

4,8 bidirectional data transfers bit rate of serial can reach 100kbit/s under mode standard, can reach 400kbit/s, can reach 3.4Mbit/s under fast mode under quick mode;

5, the maximum capacitor 400pF that the IC quantity being connected to same bus is only subject to bus limits.

Summary of the invention

The technical problem to be solved in the present invention is: the invention provides a kind of I2C line sharing steering logic method under server on-off state, overweights and solves same I2C equipment, the master & slave control under switching on and shutting down different operating state.

The technical solution adopted in the present invention is:

A kind of I2C line sharing steering logic method under server on-off state, described method for BMC when ultralow temperature cannot start, the temperature sensor of mainboard is received on CPLD logic control device, carry out the temperature of detecting master plate, and determine the need of carrying out motherboard heating function, now, CPLD is I2C main equipment, and temperature sensor is that I2C is from equipment;

After successfully starting shooting, two groups of I2C buses of BMC are switched to control CPLD and temperature sensor respectively by I2C bus switch, and now, BMC is I2C main equipment, and CPLD and temperature sensor are that I2C is from equipment.

During off-mode, FAN_SCL/SDA and CPLD is connected, and temperature information can be delivered to CPLD, so that logic control device goes to judge whether to need to open heating function according to temperature.

After system boot, FAN_CTL_IBMC signal drags down, and BMC_I2C6 and CPLD is connected, and as master slave relation, BMC can be communicated with CPLD; BMC_I2C8 and FAN_SCL/SDA is connected to make the main equipment as fan control come to control rotation speed of the fan according to corresponding thermaltable.

Described method operation steps is as follows:

1) judge that whether system is at open state;

2) if not at open state, FAN_CTL_IBMC signal is drawn high; BMC, as main equipment, connects CPLD and FAN_CTL respectively;

3) if system is at open state, judge that whether mainboard temperature is too low;

4) if mainboard temperature is not too low, then normal boot-strap, FAN_CTL_IBMC signal is drawn high; BMC, as main equipment, connects CPLD and FAN_CTL respectively;

5) if mainboard temperature is too low, then CPLD opens heating function, repeats step 3.

Beneficial effect of the present invention is:

The present invention is by when off-mode, and the control modules such as BMC manage I2C controllers such as Thermalsensor, and after start by other equipment to its management and control, with the problem do not started under solving computing machine low-temperature condition.

Accompanying drawing explanation

Fig. 1 is described method implementation step process flow diagram;

Fig. 2 is that controlling functions realizes block diagram 1

Fig. 3 is that controlling functions realizes block diagram 2

Fig. 4 is that controlling functions realizes block diagram 3.

Embodiment

With reference to the accompanying drawings, by embodiment, the present invention is further described:

Embodiment 1:

A kind of I2C line sharing steering logic method under server on-off state, described method has the possibility that cannot start for BMC when ultralow temperature, therefore the temperature sensor of mainboard is now received on the logic control devices such as CPLD, carry out the temperature of detecting master plate, and determine the need of carrying out motherboard heating function, now, CPLD is I2C main equipment, and temperature sensor (fan governor) is for I2C is from equipment;

After successfully starting shooting, two groups of I2C buses of BMC are switched to control CPLD and temperature sensor respectively by I2C bus switch, and now, BMC is I2C main equipment, and CPLD and temperature sensor (fan governor) are for I2C is from equipment.

Embodiment 2:

As shown in Figure 2,3, on the basis of embodiment 1, during the present embodiment off-mode, FAN_SCL/SDA and CPLD is connected, and temperature information can be delivered to CPLD, so that logic control device goes to judge whether to need to open heating function according to temperature.

Wherein, U145 and U144 is I2C bus switch, and slightly discrepant place is, the enable signal of these two bus switchs is just contrary.

Embodiment 3:

As shown in Figure 3,4, on the basis of embodiment 2, after the present embodiment system boot, FAN_CTL_IBMC signal drags down, and BMC_I2C6 and CPLD is connected, and as master slave relation, BMC can be communicated with CPLD; BMC_I2C8 and FAN_SCL/SDA is connected to make the main equipment as fan control come to control rotation speed of the fan according to corresponding thermaltable.

Embodiment 4:

On the basis of embodiment 2 or 3, described in the present embodiment, method operation steps is as follows:

1) judge that whether system is at open state;

2) if not at open state, FAN_CTL_IBMC signal is drawn high; BMC, as main equipment, connects CPLD and FAN_CTL respectively;

3) if system is at open state, judge that whether mainboard temperature is too low;

4) if mainboard temperature is not too low, then normal boot-strap, FAN_CTL_IBMC signal is drawn high; BMC, as main equipment, connects CPLD and FAN_CTL respectively;

5) if mainboard temperature is too low, then CPLD opens heating function, repeats step 3.

Above embodiment is only for illustration of the present invention; and be not limitation of the present invention; the those of ordinary skill of relevant technical field; without departing from the spirit and scope of the present invention; can also make a variety of changes and modification; therefore all equivalent technical schemes also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.