Methods and apparatus for debugging a system with a hung data bus
AssigneeAltera Corporation
InventorAndrew Draper
Life of this patent
Estimating the term…
Abstract
Methods and apparatus are provided to facilitate debugging of a system with a hung data bus. A register scan chain is used to read data from logic blocks of the hung system. The scan chain is also used to write data into the logic blocks, possibly resetting a subset of those blocks or otherwise causing them to exit the hung state. The resetting may terminate the hung instruction in a manner that allows subsequent instructions to be executed, including entry into debug mode.
Claims28
Circuitry for forcing an integrated circuit out of a hung state, comprising:
- at least one logic block implemented on the integrated circuit;
- and
- at least one shift register circuit implemented on the integrated circuit, associated with the at least one logic block, wherein:
- the at least one shift register circuit can write control data to the at least one logic block;
- and
- each of the at least one logic block can reset itself responsive to the value of the control data.
A method of forcing an integrated circuit out of a hung state, comprising:
- reading status data from at least one logic block implemented on the integrated circuit to at least one shift register implemented on the integrated circuit;
- shifting the status data out of the at least one shift register;
- shifting control data into the at least one shift register;
- and
- writing the control data from the at least one shift register to the at least one logic block.
Circuitry for reading status data from an integrated circuit and writing control data to the integrated circuit, comprising:
- means for reading the status data from at least one logic block implemented on the integrated circuit;
- and
- means for writing the control data from at least one shift register implemented on the integrated circuit to the at least one logic block, wherein:
- the reading and writing can be performed while the integrated circuit is in a hung state;
- and
- the writing can release the integrated circuit from the hung state.
Dependencies are inferred from the claim text.