Communication between an image forming device and a replaceable supply item

A chip configured for communication with a controller of an image forming device and mountable on a replaceable supply item for installation in the image forming device, comprising a processor and a memory;

• the memory storing program instructions for execution by the processor including instructions to receive a first write command from the controller of the image forming device, to send a first busy response to the controller of the image forming device upon receiving a first read command from the controller of the image forming device corresponding to the first write command while processing the first write command, to, after sending the first busy response, receive a second write command from the controller of the image forming device that is abbreviated relative to the first write command and that requests the chip to send a response to the first write command, to send a response to the first write command to the controller of the image forming device if upon receiving a second read command corresponding to the second write command the processor has completed processing the first write command, and to send a second busy response to the controller of the image forming device if upon receiving the second read command the processor has not completed processing the first write command.

A chip for use on a replaceable supply item of an image forming device, comprising processing circuitry configured to communicate as a slave node of an I2C communication bus with a controller of the image forming device as a master node of the I2C communication bus, the processing circuitry configured to, after sending a first busy response to the controller of the image forming device while processing a first write command received from the controller of the image forming device, receive a second write command from the controller of the image forming device that has less data than the first write command and that requests the chip on the replaceable supply item to send a response to the first write command, the processing circuitry configured to send a response to the first write command to the controller of the image forming device if upon receiving a read command corresponding to the second write command the processing circuitry is no longer processing the first write command.

A method of processing commands from a controller of an image forming device by a chip on a replaceable supply item installed in the image forming device, comprising:

• after sending a first busy response by the chip on the replaceable supply item to the controller of the image forming device while processing a first write command received by the chip on the replaceable supply item from the controller of the image forming device, receiving a second write command by the chip on the replaceable supply item from the controller of the image forming device that has less data than the first write command and that requests the chip on the replaceable supply item to send a response to the first write command;
• and
• if upon receiving a read command corresponding to the second write command the chip on the replaceable supply item is no longer processing the first write command, sending a response to the first write command by the chip on the replaceable supply item to the controller of the image forming device.

A method of facilitating electrical communication between a controller of an image forming device and a chip for use on a replaceable supply item of the image forming device, comprising:

• configuring the chip to operate as a slave node on an I2C communication bus where the controller of the image forming device serves as a master node on the I2C communication bus;
• and
• configuring the chip to receive a first write command from the controller of the image forming device, to send a first busy response to the controller of the image forming device upon receiving a first read command from the controller of the image forming device corresponding to the first write command while processing the first write command, to, after sending the first busy response, receive a second write command from the controller of the image forming device that is abbreviated relative to the first write command and that requests the chip to send a response to the first write command, to send a response to the first write command to the controller of the image forming device if upon receiving a second read command corresponding to the second write command the chip has completed processing the first write command, and to send a second busy response to the controller of the image forming device if upon receiving the second read command the chip has not completed processing the first write command.