IC, IC-mounted electronic device, debugging method and IC debugger
AssigneeFujitsu Limited
InventorsYusuke Kawasaki, Shigeru Hashimoto
Life of this patent
Estimating the term…
Abstract
Authentication circuits are provided between a debug I/F circuit and a debug terminal. The authentication circuit transmits a transmission key externally at the time of activation, and authenticates based on a reception signal and the transmission key, and enables access to the debug I/F. Thus, it is possible to prevent a spurious access from the debug I/F by a third person by the authentication circuit.
Claims17
An IC comprising:
- an internal circuit;
- a debug I/F circuit for debugging the internal circuit externally;
- and
- an authentication circuit which is provided between the debug I/F circuit and a debug terminal for connecting outside, and for transmitting a transmission key from the debug terminal to outside, and authenticating from a reception signal received from the debug terminal and said transmission key to enable operation of the debug I/F circuit,
- wherein said internal circuit comprises a CPU connected to said debug I/F circuit through a debug bus and a peripheral circuit connected to said CPU through an internal bus separated from said debug bus, wherein said CPU writes said transmission key to said authentication circuit to start transmission of the transmission key.
An electronic device mounted with an IC, said IC comprising:
- an internal circuit;
- a debug I/F circuit for debugging the internal circuit externally;
- and
- an authentication circuit which is provided between the debug I/F circuit and a debug terminal for connecting outside, and for transmitting a transmission key from the debug terminal to outside, and collating a reception signal received from the debug terminal with the transmission key to enable operation of the debug I/F circuit,
- wherein said internal circuit comprises a CPU connected to said debug I/F circuit through a debug bus and a peripheral circuit connected to said CPU through an internal bus separated from said debug bus, wherein said CPU writes said transmission key to said authentication circuit to start transmission of the transmission key.
A debugging method for utilizing a debug I/F circuit and debugging an internal circuit externally, comprising the steps of:
- transmitting a transmission key externally when the debug I/F circuit is activated;
- and
- authenticating a reception signal received externally and the transmission key to enable operation of the debug I/F circuit,
- wherein the step of authenticating further comprises connecting a CPU to said debug I/F circuit through a debug bus and connecting a peripheral circuit to said CPU through an internal bus separated from said debug bus, wherein the step of authenticating further comprises a step of starting said transmitting step by writing said transmission key to an authentication circuit with said CPU.
A debugger for debugging an IC, the IC comprising an internal circuit;
- a debug I/F circuit for debugging the internal circuit;
- and an authentication circuit which is provided between the debug I/F circuit and a debug terminal, said debugger comprising:
- a debug unit for debugging said IC;
- and
- a discrimination device which is provided between said debug unit and said debug I/F circuit, and for receiving a transmission key from said authentication circuit, encrypting said transmission key by a predetermined key, and transmitting the encrypted transmission key to said authentication circuit to enable debugging of said IC by said debug unit,
- wherein said internal circuit comprises a CPU connected to said debug I/F circuit through a debug bus and a peripheral circuit connected to said CPU through an internal bus separated from said debug bus, wherein said CPU writes said transmission key to said authentication circuit to start transmission of the transmission key.
Dependencies are inferred from the claim text.