Watchdog Timer IP Core

Features a Two-Stage Timer Supporting Non-Maskable Interrupt and a Hard Reset

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The Watchdog Timer IP Core is designed for use as an indicator that a corrective action is needed in response to a computer or a processor malfunction. The design features a two-stage timer which supports non-maskable interrupt and a hard reset.

This IP Core is a two-stage timer that starts to count depending on the computer status. The computer continuously sends a kick signal to the watchdog timer as its status, absence of the kick signal means there is a hardware malfunction or program error in the computer. Uses an up-counter that counts from zero to a timeout value at a rate that is determined by the configurable mode and the clock frequency.

Performs Two Main Functions: Send a non-maskable interrupt to the computer (nmi_o) and send a reset to the computer for system restart (reset_o).

Supports Both Warm and Cold Boot Resets - Supports both warm boot (nmi_o) and cold boot (reset_o) resets. Reset ports are asserted once the timeout value is reached. The warm boot reset is a non-maskable interrupt which serves as a warning to the computer that a system reset is expected. When this port is asserted, the computer should either debug the program error or store the important files in running programs. The cold boot or the hard reset, as the name implies, resets the whole system once the second timeout value has reached.

Features

  • Seamlessly work with sleep mode
  • Programmable timer spec 50-500 ms (10 ms)
  • Two-stage timer that supports warm boot and cold boot resets
  • You can specify in cycles or time
  • Supports trigger input, reset and NMI output

Jump to

Block Diagram

Watchdog Timer IP Core Block DiagramExpand Image

Resource Utilization

IP Configuration for Avant Family
LAV-AT-500E-3LFG1156I
Configuration Clk Fmax (MHz)1 Registers LUTs DSP
Default 245.58 51 77 0
Enable APB = Checked
Others = Default		 231.7 109 164 0
Timer Stage 1 Number of Cycles: 500,
Timer Stage 2 Number of Cycles: 500,
Others = Default		 251.76 37 57 0
Timer Stage 1 Number of Cycles: 75000000,
Timer Stage 2 Number of Cycles: 75000000,
Others = Default		 251.76 51 77 0
Mode: Time,
System Clock Frequency: 150,
Others = Default		 251.76 51 77 0
Mode: Time,
Timer Stage 1 Timeout: 500,
Timer Stage 2 Timeout: 500,
Others = Default		 251.76 52 77 0

1. Fmax is generated when the FPGA design only contains Watchdog Timer IP Core, and the target frequencies are 150 MHz (for configured System Clock Frequency) and 100MHz (for other configuration). These values may be reduced when user logic is added to the FPGA design.

IP Configuration for Nexus Family
LFMXO5-25-9BBG400I
Configuration Clk Fmax (MHz)1 Registers LUTs DSP
Default 169.66 51 100 0
Enable APB = Checked
Others = Default		 200 109 181 0
Timer Stage 1 Number of Cycles: 500,
Timer Stage 2 Number of Cycles: 500,
Others = Default		 200 37 73 0
Timer Stage 1 Number of Cycles: 75000000,
Timer Stage 2 Number of Cycles: 75000000,
Others = Default		 200 51 98 0
Mode: Time,
System Clock Frequency: 150,
Others = Default		 200 51 106 0
Mode: Time,
Timer Stage 1 Timeout: 500,
Timer Stage 2 Timeout: 500,
Others = Default		 189.97 52 107 0

1. Fmax is generated when the FPGA design only contains Watchdog Timer IP Core, and the target frequencies are 150 MHz (for configured System Clock Frequency) and 100MHz (for other configuration). These values may be reduced when user logic is added to the FPGA design.

LFMXO5-25-7BBG400I
Configuration Clk Fmax (MHz)1 Registers LUTs DSP
Default 132.14 51 100 0
Enable APB = Checked
Others = Default		 152.02 109 181 0
Timer Stage 1 Number of Cycles: 500,
Timer Stage 2 Number of Cycles: 500,
Others = Default		 170.45 36 73 0
Timer Stage 1 Number of Cycles: 75000000,
Timer Stage 2 Number of Cycles: 75000000,
Others = Default		 143.74 51 98 0
Mode: Time,
System Clock Frequency: 150,
Others = Default		 172.56 51 107 0
Mode: Time,
Timer Stage 1 Timeout: 500,
Timer Stage 2 Timeout: 500,
Others = Default		 163.99 52 107 0

1. Fmax is generated when the FPGA design only contains Watchdog Timer IP Core, and the target frequencies are 150 MHz (for configured System Clock Frequency) and 100MHz (for other configuration). These values may be reduced when user logic is added to the FPGA design.

Resource Utilization
Configuration Clk Fmax (MHz) Slice Registers LUTs EBRs
Default 175.840MHz 52 116 0
Timer Stage 1 Timeout = 1050, Others = Default 200MHz 52 117 0
Mode Time, Clock Frequency = 150, Others = Default 189.107 52 128 0
Mode Time, Timer Stage 2 Timeout = 100, Others = Default 160.154MHz 2 126 0

Ordering Information

The Watchdog Timer IP Core is available for free to use in Lattice Radiant design software.

Documentation

Quick Reference
TITLE NUMBER VERSION DATE FORMAT SIZE
Select All
Watchdog Timer IP Core - Lattice Radiant Software
FPGA-IPUG-02097 1.4 7/3/2023 PDF 512.9 KB

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