Control method for IIC bus unlocking

A control method and unlocking technology, applied in the direction of program control, computer control, general control system, etc., can solve the problems that the control unit cannot communicate with the storage unit, and the air conditioner cannot operate normally, so as to reduce the after-sales complaint rate and improve the reading accuracy rate, cost-increasing effect

Active Publication Date: 2020-04-14
NINGBO AUX ELECTRIC +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to solve the problem that the control unit cannot communicate with the storage unit after the IIC bus is locked, so that the air conditioner cannot operate normally

Method used

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  • Control method for IIC bus unlocking
  • Control method for IIC bus unlocking
  • Control method for IIC bus unlocking

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0057] The IIC bus in this embodiment includes 9 always pulses, with figure 2 It is the timing diagram of the IIC bus.

[0058] When the device is running, if the control unit MCU just sends the 9th clock pulse, SCL is at high level at this time, and the storage unit EEPROM pulls down SDA to prepare for ACK response. Under normal circumstances, after the 9th clock pulse is sent by the MCU, SCL becomes low, EEPROM can release SDA as high level.

[0059] However, if the MCU is reset during the 9th clock pulse and the EEPROM is still working normally, the SCL will always be high when the MCU is reset. At this time, EEPROM will not wait until SCL becomes low level, EEPROM will continue to respond and cannot release SDA, and SDA is always low level; after the MCU is reset, it is found that SDA is always low and it is considered occupied, and it will always wait EEPROM releases SDA high. At this point, MCU and EEPROM wait for each other, and the IIC bus enters a deadlock state. ...

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Abstract

The invention relates to a control method for IIC bus unlocking. The method is used for unlocking IIC locking in the process that a control unit reads a storage unit. The method comprises the following steps: configuring SCL and SDA pins on the control unit to be in a GPIO mode; setting an unlocking time sequence on the IIC bus, and enabling the storage unit to release SDA by operating and circulating the unlocking time sequence for N times; configuring SCL and SDA pins on the control unit to be in an IIC mode; and initializing the control unit and the storage unit. Therefore, by setting the unlocking time sequence, the IIC bus can be effectively unlocked, and the situation that the MCU cannot read EEPROM data under the condition that the IIC bus is locked is avoided.

Description

technical field [0001] The invention relates to the technical field of air conditioners, in particular to a control method for unlocking an IIC bus. Background technique [0002] The parameter values ​​processed during the operation of the air conditioner are generally stored in the memory chip, and the memory chips commonly used at present are generally EEPROMs of various capacities. The EEPROM data is usually read by the MCU when the main board of the air conditioner is powered on, and then the MCU controls the operation of the unit according to the parameters corresponding to the read EEPROM data. [0003] In practical application, during the process of MCU reading EEPROM data, the following situations will probabilistically cause the IIC bus to be locked: [0004] (1) Since the operating voltage ranges of the MCU chip and the EEPROM are often inconsistent, when the working voltage of the EEPROM is lower than that of the MCU chip, and the power supply voltage fluctuates ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05B19/042
CPCG05B19/0423G05B2219/21119
Inventor 李超
Owner NINGBO AUX ELECTRIC
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