A logic circuitry package for a replaceable print apparatus component includes an interface to communicate with a print apparatus logic circuit and at least one logic circuit. The at least one logic circuit is configured to receive, via the interface, a request and a reference clock signal. The at least one logic circuit is configured to transmit, via the interface, a digital value indicating a count in response to the request and the reference clock signal. The digital value varies based on the reference clock signal.

A logic circuitry package includes an interface to communicate with a print apparatus logic circuit and at least one logic circuit. The logic circuit is configured to receive, via the interface, a plurality of first requests in a heater disabled mode, each first request corresponding to a different sensor ID of a plurality of sensor IDs; transmit, via the interface, a first digital value in response to each first request; receive, via the interface, a plurality of second requests in a heater enabled mode, each second request corresponding to a different sensor ID of the plurality of sensor IDs; and transmit, via the interface, a second digital value in response to each second request. Delta values corresponding to a difference between the first digital value and the second digital value for each different sensor ID of the plurality of sensor IDs are indicative of a print material level.

A replaceable print apparatus component includes a print material reservoir, a print material within the reservoir and a sensing system including an integrated circuit configured to connect to and communicate over a digital bus. The sensing system includes at least one sensor, a digital controller, an analog to digital converter electrically coupled to the digital controller, and a memory array electrically coupled to the digital controller. The digital controller is configured to generate a clock signal for timing operations of the integrated circuit. The operations include initiating the at least one sensor based on values stored in the memory array and generating outputs of the at least one sensor via the analog to digital converter.

A logic circuitry package for a replaceable print apparatus component includes an I2C interface to communicate with a print apparatus logic circuit and at least one logic circuit. The at least one logic circuit is configured to respond to communications over the I2C interface that are directed to an initial or reconfigured I2C address. The at least one logic circuit is configured to receive, via the I2C interface, a write command to a first memory address of the logic circuit to initiate a first function of the logic circuit. The at least one logic circuit is configured to generate first data in response to the first function. The at least one logic circuit is configured to receive, via the I2C interface, a first read command to a second memory address of the logic circuit. The at least one logic circuit is configured to transmit, via the I2C interface, the first data in response to the first read command to the second memory address.

A logic circuitry package for a replaceable print apparatus component includes an interface to communicate with a print apparatus logic circuit and at least one logic circuit. The at least one logic circuit is configured to receive, via the interface, a request to turn on a clock generator of the logic circuitry package. The at least one logic circuit is configured to receive, via the interface, a request selecting an internal clock signal to sample. The at least one logic circuit is configured to receive, via the interface, a reference clock signal. The at least one logic circuit is configured to transmit, via the interface, a digital value indicating a count of cycles of the selected internal clock signal during a predetermined number of cycles of the reference clock signal.

A logic circuitry package for a replaceable print apparatus component includes an interface to communicate with a print apparatus logic circuit and at least one logic circuit including a memory storing a reference parameter. The at least one logic circuit is configured to receive, via the interface, a first request sent to a first address to read the reference parameter; and transmit, via the interface, the reference parameter in response to the first request. The at least one logic circuit is configured to receive, via the interface, a second request sent to a second address to implement a task; and implement the task to output a digital value via the interface in response to the second request. The reference parameter corresponds to the digital value.

In one example a liquid level sensing device is described. The device includes a carrier and a liquid level sensing device disposed on the carrier. The liquid level sensing interface has an aspect ratio of at least 1:50. A number of liquid level sensing components are disposed on the liquid level sensing interface. The number of liquid level sensing components detect a liquid level in a liquid container. The liquid level sensing device also includes an electrical interconnect to output data collected from the number of liquid level sensing components.

An apparatus and a method for measuring fluid flow parameters. The apparatus can have a plurality of upstream sensors and a plurality of downstream sensors in communication with a computer. By comparing the sensor reading to an ambient condition, or a known fluid characteristic, the presence of fluid can be determined. The computer can utilize measured data from the sensors and known sensor placement to calculate volumetric flow rate and make determinations about equipment health.

In one example in accordance with the present disclosure a fluid property sensing device is described. The fluid property sensing device includes a substrate having a trench formed therein. The trench includes a bottom surface and opposite side surfaces. A first electrode is disposed on a first side surface of the trench and a second electrode is disposed on a second side surface of the trench. The first electrode and second electrode form a capacitor to measure a complex impedance of a fluid that fills a space between the first electrode and the second electrode. This complex impedance indicates a property of the fluid. A fluid level sensing die, having a number of fluid level sensing components disposed thereon, may be attached to the substrate, preferably in such a way that the fluid level sensing die is surrounded by the trench. In this way the surface area of the electrodes provided in the trench can be increased. The number of level sensing components may be thermal sensing components.

In one example a liquid level sensor is described. The sensor includes a carrier and a liquid level sensing interface disposed on the carrier. The liquid level sensing interface includes a number of liquid level sensing devices disposed on an elongated strip. The number of liquid level sensing devices detect a liquid level in a liquid container. The liquid level sensing interface also includes a number of thermal isolation components formed on the elongated strip to thermally isolate adjacent liquid level sensing devices.