BACKGROUND

[0001] Fluid-jet printing devices eject, or jet, fluid. For example, in the case of image-forming fluid-jet printing devices, the devices can eject fluid like ink onto print media like paper to form images on the media. In the case of three- dimensional (3D) fluid-jet printing devices, the devices can additively eject fluid like 3D print material or binder fluids onto a substrate to form 3D objects in a layer-by-layer manner. Fluid-jet printing devices are used in a variety of different environments, including enterprise, consumer, and print service provider (PSP) environments. A fluid-jet printing device can include replaceable components, such as printhead dies, which may be part of fluid-jet cartridges that also include supplies of fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 is a diagram of an example fluid-jet printhead die for a printing device.

[0003] FIG. 2 is a diagram of an example fluid-jet element that can be used in the printhead die of FIG. 1.

[0004] FIG. 3 is a diagram of an example extra functionality circuit that can be used in the printhead die of FIG. 1. [0005] FIG. 4 is a diagram of an example selection sub-circuit that can be used in the extra functionality circuit of FIG. 3. [0006] FIGs. 5 and 6 are timing diagram of example print periods by which printing devices use the printhead die of FIG. 1.

[0007] FIG. 7 is a block diagram of an example electronic component, such as a fluid-jet printhead die. [0008] FIG. 8 is a block diagram of an example fluid-jet printhead die.

[0009] FIG. 9 is a flowchart of an example method by which printing devices use the printhead die of FIG. 8.

DETAILED DESCRIPTION

[0010] As noted in the background, a fluid-jet printing device can include a replaceable printhead die, which may be part of a fluid-jet cartridge that also includes supplies of fluid for use by the device. A fluid-jet printhead die can include individually addressable fluid-jet elements, such as firing resistors, which in the case of image formation the printing device can selectively actuate, or fire, to form an image on print media as the media and the die move relative to one another. The printhead die directly or indirectly interfaces with the printing device via conductive pads.

[0011] Given types of fluid-jet printing devices are thus compatible with given types of printhead dies. For a printhead die to be compatible with a fluid-jet printing device, the printhead die has to be able to properly interface with the printing device, among other things. For example, if the printhead die is part of a fluid-jet cartridge, the cartridge has to physically fit within or otherwise connect to the printing device, with conductors of the cartridge that are connected to conductive pads of the die making electrical contact with corresponding conductors of the device.

[0012] Adding capabilities or extra functionality to a fluid-jet printhead die while retaining backwards compatibility with a given type of fluid-jet printing device is therefore difficult without adding or replacing hardware within the printing device. The printing device may have to communicate with printhead die in a particular way to invoke the extra functionality added to the printhead die. However, such communication is limited to the existing electrical interface between the die and the device. [0013] Techniques described herein provide ways by which extra functionality can be added to a fluid-jet printhead die for use within a fluid-jet printing device without having to add or replace hardware within the printing device. The printhead die includes address lines and fluid-jet elements that are organized in groups correspondingly connected to the address lines. An extra functionality circuit performs functionality other than fluid-jet element firing in an extra functionality mode, which the die enters responsive to (e.g., which the printing device selects via) assertion of more than one address line.

[0014] The fluid-jet printhead die includes address pads that are correspondingly connected to the address lines and that interface the die with the printing device. The address pads can configurationally correspond to the address pads of a legacy fluid-jet printhead die lacking the extra functionality circuit (and thus the extra functionality mode). The printhead die can thus be backwards compatible in that the printing device can use the printhead die as if the die were a legacy fluid-jet printhead die lacking the extra functionality circuit (and thus the extra functionality mode).

[0015] For instance, a fluid-jet printing device may use a particular type of legacy fluid-jet printhead die that lacks the extra functionality circuit. The printing device may individually assert the legacy printhead die’s address lines (i.e. , one at a time) via their corresponding address pads on the die when selectively firing the die’s fluid-jet elements. Since the address pads of the disclosed fluid-jet printhead die can configurationally correspond to the legacy printhead die’s address pads, the disclosed die can still be used in such a printing device, even if the device is unable to use the extra functionality mode.

[0016] A fluid-jet printing device may thus be upgradeable to use the extra functionality mode of the disclosed fluid-jet printhead die without having to replace or add hardware in the printing device. The extra functionality mode of the printhead die is invoked over the same address lines that are used when firing the die’s fluid-jet elements, with the difference being that more than one address line is asserted to invoke the extra functionality mode. A printing device that is compatible with a legacy fluid-jet printhead die with which the disclosed printhead die’s address pads configurationally correspond can therefore be programmed to use the disclosed die’s extra functionality mode, so long as the device’s firmware or other software is upgradable.

[0017] FIG. 1 shows an example fluid-jet printhead die 100 for a fluid-jet printing device. For example, the printhead die 100 may be an inkjet printhead die for an inkjet-printing device. The printhead die 100 is more generally an electronic component, and the printing device is more generally an electronic device. Therefore, the printhead die 100 is more generally an electronic component for an electronic device. The printhead die 100 includes fluid-jet elements 102, which can be organized over rows 104 and columns 106, as in the example of FIG. 1. The rows 104 of the fluid-jet elements 102 can more generally be referred to as groups, whereas the columns 106 can more generally be referred to as primitives. The fluid-jet elements 102 are individually addressable, and are actuated or fired to cause the elements 102 to eject fluid, like ink. [0018] The fluid-jet printhead die 100 includes an M-bit address bus 108 made up of M one-bit address lines 110A, 110B, . . ., 110M, which are collectively referred to as the address lines 110. The address lines 110 are correspondingly connected to the rows 104 of the fluid-jet elements 102. That is, each address line 110 is connected to the fluid-jet elements 102 within a corresponding row 104, with each address line 110 connected to a different row 104 of the elements 102. The number or rows 104 can therefore be equal to the number of address lines 110, and is more generally equal to or less than the number of address lines 110.

[0019] The fluid-jet printhead die 100 includes an N-bit primitive bus 112 made up of N one-bit primitive lines 114A, 114B, . . ., 114N, which are collectively referred to as the primitive lines 114. The primitive lines 114 are correspondingly connected to the columns 106 of the fluid-jet elements 102.

That is, each primitive line 114 is connected to the fluid-jet elements 102 within a corresponding column 106 of the elements 102, with each primitive line 114 connected to a different column 106 of the elements 102. The number of columns 106 can therefore be equal to the number of primitive lines 114, and more generally is equal to or less than the number of primitive lines 114. The N number of primitive lines 114 can be equal to, less than, or greater than the M number of address lines 110.

[0020] Assertion of an address line 110 selects the fluid-jet elements 102 connected to the row 104 to which the address line 110 corresponds. Likewise, assertion of a primitive line 114 selects the fluid-jet elements 102 connected to the column 106 to which the primitive line 114 corresponds. Each fluid-jet element 102 is therefore individually addressable via assertion of both the address line 110 connected to the row 104 including the element 102 and the primitive line 114 connected to the column 106 including the element 102. [0021] The fluid-jet printhead die 100 includes M address pads 116 connected to the address bus 108 and thus correspondingly connected to the address lines 110. Each address pad 116 is connected to a different address line 110 of the address bus 108. The fluid-jet printhead die 100 includes N primitive pads 118 connected to the primitive bus 112 and thus correspondingly connected to the primitive lines 114. Each primitive pad 118 is connected to a different primitive line 114 of the primitive bus 112.

[0022] The fluid-jet printhead die 100 interfaces with a printing device via the address pads 116 and the primitive pads 118. For instance, wires or other types of conductive traces may conductively connect the pads 116 and 118 of the printhead die 100 to corresponding pads on the printing device. As another example, the printhead die 100 may be part of a fluid-jet cartridge that also includes supplies of fluid. Wires or other types of conductive traces may conductively connect the pads 116 and 118 of the printhead die 100 to the cartridge, with the cartridge then making conductive contact with the printing device upon insertion into or connection to the device. The printhead die 100 may include pads other than the address pads 116 and the primitive pads 118. [0023] In a firing mode, the fluid-jet printhead die 100 selectively ejects fluids from the fluid-jet elements 102. In the firing mode, the printhead die 100 individually asserts the address lines 110 one at a time, to correspondingly select the rows 104 of the fluid-jet elements 102 one row at a time. While asserting a given address line 110, the printhead die 100 also selectively asserts the primitive lines 114, to correspondingly select the columns 106 of the fluid-jet elements 102. The fluid-jet elements 102 within the selected row 104 and the selected columns 106 (i.e. , each element 102 is connected to the asserted address line 110 as well as to any asserted primitive line 114) is thus actuated or fired, causing fluid to be ejected from the die 100.

[0024] The fluid-jet printhead die 100 includes an extra functionality circuit 120. The extra functionality circuit 120 performs functionality other than fluid-jet element firing, in an extra functionality mode. Examples of such extra functionality include thermal and strain sensing, blocked fluid-jet nozzle detection, and closed-loop thermal control, among other types of such extra functionality. [0025] The extra functionality circuit 120 of the fluid-jet printhead die 100 is connected to a subset 122 of L<M address lines 110 of the address bus 108.

The subset 122 of the address lines 110 includes more than one address line 110. The extra functionality circuit 120 performs its associated functionality in an extra functionality mode, in which the subset 122 of the address lines 110 is asserted. Stated another way, assertion of the subset 122 of the address lines 110 by the printing device to which the printhead die 100 is interfaced causes the die to enter the extra functionality mode and thus causes the extra functionality circuit 120 to perform its associated functionality. [0026] The printing device to which the fluid-jet printhead die 100 is connected therefore selectively fires the fluid-jet elements 102 when individually asserting the address lines 110, in a firing mode of the printhead die 100. By comparison, the printing device causes the extra functionality circuit 120 to perform functionality other than fluid-jet element firing by simultaneously asserting the subset 122 of the address lines 110, in an extra functionality mode of the printhead die 100. In both cases, the same address pads 116 are used, with the difference being that just one address line 110 (via its corresponding address pad 116) is asserted at a time in the firing mode, and more than one address line 110 (specifically the subset 122 of the address lines 110, via their corresponding address pads 116) are simultaneously asserted in the extra functionality mode.

[0027] FIG. 2 shows an example fluid-jet element 200 for a fluid-jet printhead die. Each of the fluid-jet elements 102 of the fluid-jet printhead die 100 of FIG. 1 can be implemented as a fluid-jet element 200. The fluid-jet element 200 includes a firing resistor 202 and a transistor 204 in series with one another, between a primitive line 114 and ground. The firing resistor 202 can also be referred to as a heating resistor. The transistor 204 has its gate connected to an address line 110.

[0028] Assertion of the address line 110 and the primitive line 114 selects and thus fires the fluid-jet element 200, causing current to flow through the firing resistor 202. When current flows through the firing resistor 202, the resistor 202 increases in temperature. This temperature increase in turn heats fluid surrounding the firing resistor 202, forming a bubble within the fluid, which results in ejection of a droplet of the fluid from fluid-jet element 200.

[0029] FIG. 3 shows an example extra functionality circuit 300 for a fluid- jet printhead die. The extra functionality circuit 120 of FIG. 1 can be implemented as the extra functionality circuit 300. The extra functionality circuit 300 includes a selection sub-circuit 302 and a functionality sub-circuit 304. Each of the circuits 302 and 304 can include discrete electronic components, such as resistors, capacitors, inductors, and so on, as well as complex electronic components, such as integrated circuits (ICs), field-programmable gate arrays (FPGAs), and so on, to perform its respective functionality. The circuits 302 and 304 may be separate from one another, or integrated in the same IC or other complex electronic component.

[0030] Of the subset 122 of L<M address lines connected to the extra functionality circuit 300, a selection subset 308 of K<L address lines is connected to the selection sub-circuit 302, and a data input subset 310 of J<L address lines is connected to the functionality sub-circuit 304. The sum of the K address lines of the selection subset 308 and the J address lines of the data input subset 310 can be equal to the L address lines of the subset 122, and more generally can be equal to or less than the L address number of the subset 122. There is more than one address line within the selection subset 308; that is, K>1. Furthermore, there may be no address lines within the data input subset 310, such that the data input subset 310 is not present; that is, J=0 and K=L. When present, the data input subset 310 can include as few as one address line; that is, J>1. The J number of address lines within the data input subset 310 may be greater than, equal to, or less than the K number of address lines within the selection subset 308.

[0031] The selection sub-circuit 302 can be connected to the functionality sub-circuit 304 by a one-bit enable line 306. In operation, the printing device to which the printhead die including the extra functionality circuit 300 is connected selectively asserts the address lines within the selection subset 308 of K address lines in a specified manner, which causes the sub-circuit 302 to assert the enable line 306. That the selection subset 308 of K address lines is asserted in a specified manner means that two or more address lines within the subset 308 are specifically asserted, and that one or more address lines within the subset 308 are specifically not asserted.

[0032] For example, the specified manner may be a specific pattern of the address lines of the selection subset 308, such as all the K address lines; the first, second, and fourth address lines where there are four address lines; and so on. However, the address lines of the selection subset 308 that are selectively asserted exceed one in number. If the selection subset 308 is not asserted in the specified manner, then the selection sub-circuit 302 does not assert the enable line 306. Therefore, the fluid-jet printhead die of which the extra functionality circuit 300 is a part enters the extra functionality mode responsive to assertion of the selection subset 308 of K address lines in the specified manner.

[0033] An address line being asserted means that the address line is driven to a first state, and an address line not being asserted means that the address line is driven to a second state. For example, driving the address line to a first state may mean that a higher voltage is applied to the address line, and driving the address line to a second state may mean that a lower voltage is applied to the address line. The first and second states may respectively correspond to logic one and logic zero, or vice-versa. [0034] Upon assertion of the enable line 306, the functionality sub-circuit

304 performs the extra functionality associated with the extra functionality circuit 300. If the data input subset 310 is present, then the functionality sub-circuit 304 performs the extra functionality based on data received on the J address lines of the data input subset 310. In operation, the printing device to which the printhead die including the extra functionality circuit 300 asserts the selection subset 308 of K address lines in the specified manner and can selectively assert the data input subset 310 of J address lines. Assertion of the selection subset 308 in the specified manner causes the selection sub-circuit 302 to assert the enable line 306, which causes the functionality sub-circuit 304 to perform its associated functionality based on the data received on the data input subset 310 per the J address lines being selectively asserted.

[0035] FIG. 4 shows an example selection sub-circuit 400. The selection sub-circuit 302 of FIG. 3 can be implemented as the selection sub-circuit 400.

The selection subset 308 includes K address lines 404A, 404B, . . ., 404K, which are collectively referred to as the address lines 404. In the example of FIG. 4, the specified manner in which the selection subset 308 is selectively asserted to enter the extra functionality mode is the assertion of every address line 404 within the selection subset 308. The selection sub-circuit 400 thus can include a logical AND gate 402, which can be implemented as a discrete electronic component or as part of a complex electronic component like an IC. If the specific manner in which the selection subset 308 is selectively asserted is other than assertion of every address line 404 within the selection subset 308, then the selection sub-circuit 400 may be implemented in a manner other than the logical AND gate 402.

[0036] The K address lines 404 of the selection subset 308 are input to the logical AND gate 402. If the specific manner in which the selection subset 308 is selectively asserted is other than assertion of every address line 404 within the subset 308, then each address line 404 that is to remain unasserted may be connected to the logical AND gate 402 via an intervening inverter. The enable line 306 is output from the logical AND gate 402. Therefore, in the example of FIG. 4, when every address line 404 of the selection subset 308 is asserted, then the output of the logical AND gate 402 is one and the enable line 306 is correspondingly asserted. If any address line 404 of the selection subset 308 is not asserted, then the output of the logical AND gate 402 is zero and the enabled line 306 is correspondingly not asserted in this example. [0037] FIG. 5 shows a timing diagram of an example print period 500 in which a fluid-jet printing device controls a fluid-jet printhead die connected to the printing device and that has an extra functionality mode. In the example of FIG. 5, there are four address lines 502 and four primitive lines 504 within the printhead die under control. The example print period 500 includes a firing part 506 and an extra functionality part 508.

[0038] In the firing part 506 of the print period 500, the printing device individually asserts the address lines 502 in succession. The address lines 502 may be addressable via four bits, with each bit corresponding to a different address line 502. A logic one corresponds to an address line 502 being asserted, whereas a logic zero corresponds to an address line 502 not being asserted.

Therefore, in the firing part 506 of the print period 500, the addresses 0001, 0010, 0100, 1000 are consecutively loaded onto the address lines 502 to successively and individually assert the address lines 502.

[0039] In the firing part 506, while an address line 502 is asserted, the printing device also selectively asserts the primitive lines 504. The primitive lines 504 may also be addressable via four bits, with each bit corresponding to a primitive line 504, a logic one corresponding to a primitive line 504 being asserted, and a logic zero corresponding to a primitive line 504 not being asserted. Therefore, in the firing part 506 of the print period 500, primitives are consecutively loaded onto the primitive lines 504 as the address lines 502 are individually asserted to selectively assert the primitive lines 504. This is indicated by the primitives ???? in FIG. 5, since which primitive lines 504 are asserted differs depending on which primitive lines 504 are selected. That is, four question marks are used to indicate the primitives in FIG. 5, since each primitive line 504 can be asserted or unasserted (e.g., can have a logic one or a logic one loaded onto it).

[0040] As such, in the firing part 506 of the print period 500, the printing device selectively and individually asserts the address lines 502 and selectively asserts the primitive lines 504 to selectively fire the fluid-jet elements in the firing mode of the fluid-jet printhead die. For a given row, or group, of fluid-jet elements selected via assertion of its corresponding address line 502, the elements within that row that are also within columns, or primitives, selected via assertion of their corresponding primitive lines 504 are selected. These selected fluid-jet elements are therefore fired and eject fluid from the printhead die.

[0041] In other words, in the firing part 506, as the rows, or groups, of fluid-jet elements are individually selected via individual assertion of their corresponding address lines 502, the elements that are also within columns, or primitives, which have been selected via assertion of their corresponding primitive lines 504 eject fluid. Flowever, in the firing part 506, the extra functionality circuit of the fluid-jet printhead die does not perform its associated functionality. This is because during the firing part 506, at most one address line 502 is asserted at any given time.

[0042] By comparison, in the extra functionality part 508 of the print period 500, the printing device simultaneously asserts more than one address line 502, specifically a selection subset of the address lines 502 that selective assertion of which in a specified manner causes the printhead die to enter the extra functionality mode. In the example of FIG. 5, the selection subset includes the address lines 502 corresponding to the two lowest bits, and the specified manner is the assertion of both these address lines 502. Therefore, the address lines 502 of the selection subset in the example 502 are simultaneously addressable by the address ??11.

[0043] In the extra functionality part 508, while the selection subset of the address lines 502 is asserted in the specified manner, the printing device can also selectively assert other address lines 502, specifically a data input subset of the address lines 502. The extra functionality circuit of the printhead die can performs its associated functionality based on data loaded on the data input subset of the address lines 502. In the example of FIG. 5, the data input subset includes the address lines 502 corresponding to the highest two bits, which are represented by question marks in the address ??11 , because which of these address lines 502 are asserted differs depending on the data that is loaded. [0044] As such, in the extra functionality part 508 of the print period 500, the printing device simultaneously asserts the address lines 502 of the selection subset in the specified manner and selectively asserts the address lines 502 of the data input subset. The printhead die enters the extra functionality mode because the selection subset of the address lines 502 has been asserted in the specified manner. The printhead die performs the functionality associated with the extra functionality mode based on data that the printing device sends on the data input subset of the address lines 502.

[0045] During the extra functionality part 508 of the print period 500, the printing device does not assert any of the primitive lines 504. By not asserting any of the primitive lines 504, the printing device ensures that inadvertent firing of fluid-jet elements is avoided. That is, simultaneous selection of more than one address line 502 during the extra functionality part 508 still selects the rows, or groups, of fluid-jet elements to which the asserted address lines 502 are connected. However, so long as none of the primitive lines 504 is asserted, no column, or primitive, of fluid-jet elements is selected, such that no fluid-jet elements are fired. [0046] In another implementation, the printhead die may have circuitry that is enabled when the selection subset of the address lines 502 is asserted in the specified manner. This circuitry may prevent the fluid-jet elements from being fired. Therefore, in such an implementation, even if the printing device inadvertently asserts any primitive line 504 during the extra functionality part 508 of the print period 500, no fluid-jet elements will be fired.

[0047] FIG. 6 shows a timing diagram of an example print period 600 in which a fluid-jet printing device controls a fluid-jet printhead die connected to the printing device and that has an extra functionality mode. However, in the example of FIG. 6, the printing device does not use and may be incapable or otherwise unable of using the extra functionality mode of the printhead die. Therefore, FIG. 6 shows how a printhead die that has an extra functionality mode can still nevertheless be backwards compatible with printing devices that cannot take advantage of such extra functionality.

[0048] In the example of FIG. 6, as in FIG. 5, there are four address lines 502 and four primitive lines 504 within the printhead die, which are addressable as has been described in relation to FIG. 5. The printing device selectively and individually asserts the address lines 502 and selectively asserts the primitive lines 504 to selectively fire the fluid-jet elements in the firing mode of the printhead die. For a given row, or group, of fluid-jet elements selected via assertion of its corresponding address line 502, the elements within that row, or group, that are also within columns, or primitives, selected via assertion of their corresponding primitive lines 504 are selected. These selected fluid-jet elements are thus fired and eject fluid from the printhead die.

[0049] In the example of FIG. 6, however, selective firing of the fluid-jet elements occurs over the duration of the print period 600, as opposed to within just a firing part 506 of the print period 500 in FIG. 5. This is because a legacy fluid-jet printhead lacking the extra functionality mode may not be able to selectively fire its fluid-jet elements more quickly than the print period 600. By comparison, a fluid-jet printhead having the extra functionality mode may be able to selectively fire its fluid-jet elements more quickly, within just the firing part 506 of the print period 500. [0050] Therefore, where the print period 500 of FIG. 5 is equal in duration to the print period 600 of FIG. 6, a printhead having the extra functionality mode can maintain the performance of a legacy printhead lacking the extra functionality mode, while still performing extra functionality (during the extra functionality part 508 of the print period 500). If a printhead having the extra functionality mode is used with a printing device that cannot leverage the extra functionality mode, then firing the fluid-jet elements occurs more slowly as in the print period 600, as compared to if the printing device can and does leverage the extra functionality mode as in the print period 500. Flowever, the firing rate is no slower than that afforded by a legacy printhead lacking the extra functionality mode.

[0051] FIG. 7 shows an example electronic component 700 for an electronic device. The electronic component 700 may be a fluid-jet printhead for a fluid-jet printing device as has been described, for instance. The electronic component 700 includes address lines 702 and addressable elements 704 organized in groups, such as rows, which are correspondingly connected to the address lines 702. Assertion of an address line 702 selects the elements 704 in the group connected to the asserted address line 702. The electronic component 700 include an extra functionality circuit 706 having associated functionality and connected to a subset of the address lines 702. The subset includes more than one of the address lines 702. The extra functionality circuit 706 is to perform the associated functionality in an extra functionality mode in which the subset of the address lines 702 is asserted. [0052] FIG. 8 shows an example fluid-jet printhead die 800 for a printing device. The printhead die includes address lines 802, and addressable fluid-jet elements 804 organized in rows, such as groups, which are correspondingly connected to the address lines 802. The printhead die 800 includes address pads 806 correspondingly connected to the address lines 802 to interface the die 800 with the printing device. The printhead die 800 includes an extra functionality circuit 808 to perform functionality other than fluid-jet element firing in an extra functionality mode. The printhead die 800 is to enter the extra functionality mode responsive to assertion of more than one address line 802. [0053] FIG. 9 shows an example non-transitory computer-readable data storage medium 900. The computer-readable data storage medium 900 stores program code 901. The program code 901 is executable by a printing device connected to a fluid-jet printhead die having fluid-jet elements organized within groups and primitives, such as rows and columns, to perform processing. The processing includes, during a firing part of a print period and in a firing mode (902), individually asserting address lines correspondingly connected to the groups to select the fluid-jet elements within the group connected to the asserted address line (904).

[0054] The processing includes, during the firing part of the print period and in the firing mode (902), while each address line is asserted, selectively asserting primitive lines correspondingly connected to the primitives to select the fluid-jet elements within the primitives connected to the asserted primitive lines (906). The fluid-jet elements connected to the asserted address line and the asserted primitive lines fire. The processing includes during an extra functionality part of the print period and in an extra functionality mode (908), asserting a subset of the address lines to cause the die to perform functionality other than fluid-jet element firing (910). The subset includes more than one of the address lines.

[0055] A fluid-jet printhead die, which is more generally an electronic component, has been described that has an extra functionality mode that is selected using the same address lines that are used to select fluid-ejection elements of the printhead die in a firing mode. Whereas the firing mode is selected via individual assertion of the address lines, the extra functionality mode is selected via assertion of more than one address line. The fluid-jet printhead die can therefore be used in place of a legacy printhead die that lacks the extra functionality mode but in which the firing mode is still selected via individual assertion of address lines. The fluid-jet printhead die can permit printing devices that use the legacy printhead die to be upgraded to use the extra functionality mode of the described printhead die without having to add or replace hardware within the device.