Abstract: Examples herein describe techniques for testing a receiver interface on a die. In one embodiment, the die includes tester circuitry which includes a digital to analog convertor (DAC) which outputs an analog test signal to a selector circuit (e.g., a multiplexer) which forwards the analog test signal to a receiver. By varying the analog test signal, the tester circuitry can identify one or more trip points corresponding to the receiver. That is, by monitoring the output of the receiver, a testing application can determine when the output of the receiver switches states thereby indicating that the analog test signal at the input of the receiver corresponds to the trip point of the receiver. In this manner, internal circuitry (e.g., the tester circuitry) can be used to test a receiver interface that may otherwise be inaccessible.

Abstract: Examples of the present disclosure provide example devices that include an integrated circuit that has debugging capability. In some examples, a device includes an integrated circuit die. The integrated circuit die includes an input/output (IO) base cell and a debug port. The IO base cell has an interface node and a feedback node. The interface node is configured to be coupled to memory, such as via an interposer, for communication therebetween. The IO base cell is configurable to selectively output to the feedback node a signal that is on the interface node. The debug port has an input node and an output node. The input node is electrically connected to the feedback node. The debug port is configurable to selectively output to the output node a signal that is on the input node. The output node is configured to be coupled to a pin exterior to the integrated circuit die.

Abstract: Examples herein describe a die that includes a testing system (e.g., testing circuitry) for measuring the actual resistance of on-die resistors. When testing the die, an I/O element (e.g., a solder bump) can be used to sweep a voltage across the on-die resistor. The testing system identifies when the voltage across the on-die resistor reaches a predefined reference voltage and measures the corresponding current. Using the measured current and the reference voltage, the testing system can identify the actual resistance of the on-die resistor. In one embodiment, the on-die resistor is tunable such if the on-die resistor has a divergent value, the die can adjust its resistance value to the desired value.

Abstract: A second controller is communicated with from a first controller via an interface. Storage is also communicated with from the first controller via the interface. The first controller is configured to be a master on the interface and the second controller and the storage are configured to be targets on the interface.

Abstract: In an example implementation, a level-shifter circuit in an integrated circuit (IC) includes a plurality field-effect transistors (FETs) coupled to provide: a first inverter having an input port configured to receive an input signal having a first supply voltage, an output port, and a bias port; a second inverter having an input port coupled to the output port of the first inverter, an output port, and a bias port coupled to a second supply voltage; a diode-connected FET coupled between the second supply voltage and the bias port of the first inverter; a first FET in parallel with the diode-connected FET having a gate coupled to the output of the second inverter; and a second FET in parallel with the diode-connected FET and the first FET having a gate configured to receive a mode select signal.

Abstract: In an example implementation, a level-shifter circuit in an integrated circuit (IC) includes a plurality field-effect transistors (FETs) coupled to provide: a first inverter having an input port configured to receive an input signal having a first supply voltage, an output port, and a bias port; a second inverter having an input port coupled to the output port of the first inverter, an output port, and a bias port coupled to a second supply voltage; a diode-connected FET coupled between the second supply voltage and the bias port of the first inverter; a first FET in parallel with the diode-connected FET having a gate coupled to the output of the second inverter; and a second FET in parallel with the diode-connected FET and the first FET having a gate configured to receive a mode select signal.

Abstract: A second controller is communicated with from a first controller via an interface. Storage is also communicated with from the first controller via the interface. The first controller is configured to be a master on the interface and the second controller and the storage are configured to be targets on the interface.

Abstract: A second controller is communicated with from a first controller via an interface. Storage is also communicated with from the first controller via the interface. The first controller is configured to be a master on the interface and the second controller and the storage are configured to be targets on the interface.

Abstract: An integrated circuit has an E-fuse sense circuit configured to produce a READ voltage according to a fuse resistance of an E-fuse during a READ operation. The integrated circuit also has a reference sense circuit configured to produce a reference voltage according to a reference resistance of an on-chip reference resistor during the READ operation. The reference sense circuit replicates the E-fuse sense circuit. The E-fuse sense circuit and the reference sense circuit are coupled to a comparator that produces a bit value according to a difference between the READ voltage and the reference voltage.

Abstract: A programmable differential signaling system includes a programmable bias generator and a plurality of input/output modules. The programmable bias generator is operably coupled to generate a first global bias signal and a second global signal based on desired signal properties of one of a plurality of differential signaling conventions. The a plurality of input/output modules is operably coupled to convert between differential signaling and single ended signaling, wherein actual signal properties of the differential signaling are regulated based on the first and second global bias signals to substantially equal the desired signal properties.

Abstract: Low current differential signal/swing I/O interfaces and techniques can be implemented. An output interface converts input data signals to differential current signals for transmission over transmission lines. When the differential current signals are received by an input interface, they are converted to differential voltage signals and appropriately amplified.

Abstract: A programmable differential signaling system includes a programmable bias generator and a plurality of input/output modules. The programmable bias generator is operably coupled to generate a first global bias signal and a second global signal based on desired signal properties of one of a plurality of differential signaling conventions. The a plurality of input/output modules is operably coupled to convert between differential signaling and single ended signaling, wherein actual signal properties of the differential signaling are regulated based on the first and second global bias signals to substantially equal the desired signal properties.

Abstract: Apparatus and method for providing reference voltages for differential signaling with tracking of output differential voltage relative to output offset voltage are described. A swing reference voltage, an offset reference voltage, a swing feedback voltage, and an offset feedback voltage are obtained. Differences between pairs of these voltages are differentially amplified to produce first and second bias voltages. Pull-up and pull-down voltages are driven partially responsive to the first bias voltage and the second bias voltage to provide first and second control voltages. The first control voltage may be provided to a first resistance for the driving of the first pull-up and pull-down voltages. The second control voltage may be provided to a second resistance for the driving of the second pull-up and pull-down voltages. The first control voltage and the second control voltage may be provided to a third resistance.

Abstract: A test-mode circuit allows the same pad of a semiconductor device to be used as a test pad during test operations and as an I/O pad during normal operations. The test-mode circuit is coupled between the pad and a reference signal (Vbg) of the device, and in response to a control signal (CTRL1) either couples the pad and the reference signal (Vbg) together or isolates the pad and the reference signal (Vbg) from each other. The test-mode circuit includes at least one NMOS transistor (MN1) and a PMOS transistor (MP1) connected in series between the pad and the reference signal (Vbg). During normal operation, the NMOS transistor (MN1) isolates the reference signal (Vbg) from the pad, and the PMOS transistor (MP1) compensates for voltage undershoot conditions at the pad.

Abstract: A power-on reset circuit for generating a reset signal for an associated IC device includes a pull-up resistor connected between a supply voltage and a tracking node, a pull-down transistor connected between the tracking node and ground potential, and a voltage divider circuit connected between the supply voltage and ground potential. The voltage divider circuit has a first ratioed voltage node coupled to the gate of the pull-down transistor. For some embodiments, the voltage divider circuit includes a first resistor connected between the voltage supply and the first ratioed voltage node, a second resistor connected between the first ratioed voltage node and a second ratioed voltage node, a third resistor connected between the second ratioed voltage node and ground potential, and a shunt transistor connected between the second ratioed voltage node and ground potential has a gate responsive to the reset signal.

Abstract: An input circuit includes a first buffer having a first power terminal coupled to a first supply voltage, a second power terminal coupled to ground potential, an input to receive an input signal, and an output to generate a first output signal, a second buffer having a first terminal coupled to a second supply voltage, a second terminal coupled to a bias node, an input to receive the input signal, and an output to generate a second output signal, and a control circuit configured to selectively connect the bias node either to the second supply voltage or to ground potential in response to an enable signal.

Abstract: A technique and circuit implementation are described for automatically detecting a change in a power supply voltage and selectively reconfiguring a circuit for optimized performance at the changed voltage. One application of particular interest is an auto-detect level shifter. The auto-detect level shifter can be used in an output driver and can be automatically enabled if it is needed to optimize performance for various I/O standards, including those that operate at different voltages.

Abstract: A self-regulating ramp up circuit generates a high voltage signal having a slow, smooth ramp up and reduced process and temperature variation. The circuit uses a resistor and a capacitor to control the rate at which the output signal changes state. In one embodiment, an enable signal operating at a low voltage level is shifted to the desired high voltage level using a level shifter. The resulting value is inverted using an inverter operating at the high voltage level and having a resistor in the pulldown path. The circuit output node is coupled to the output node of the inverter through a capacitor, and to the high voltage power supply through a pullup gated by the output node of the inverter. In some embodiments, the ramp up circuit forms a portion of a programmable logic device (PLD), and the capacitor and/or resistor have programmable capacitance/resistance values.

Abstract: A low-voltage output circuit configurably providing a bus-hold function and a weak pull-up function, while having only transitory leakage current through the circuit regardless of the voltage level on the pad. Thus, the output circuit can be used in low-voltage devices that interface with higher-voltage devices without paying the penalty of increased leakage current. One embodiment of the invention includes a circuit output node coupled to a configurable weak pull-up circuit, a configurable bus hold circuit, and a configurable leakage prevention circuit. The configurable circuits are controlled by configuration signals that determine which circuits are active. One embodiment is implemented as a portion of a programmable logic device (PLD), and the configuration signals are programmed into configuration memory cells as part of the configuration of the PLD.

Abstract: Output circuits that provide compatibility with various input and output voltage levels without sacrificing performance. A pull-up on an output terminal is gated by an internal node, and the invention encompasses various circuits and means for placing a data input signal on this internal node. One embodiment includes a level shifter on the data input path, while also providing an alternative path through the output circuit that bypasses the level shifter. When the input data value goes high, the alternative path quickly places an attenuated high value on the internal node. The level shifter then becomes active and raises the voltage on the internal node to the output power high level, ensuring that the output pull-up is completely off.