Communication apparatus implementing time domain isolation with restricted bus access

A method of operating a communication apparatus including a radio frequency (RF) circuit and a digital processing circuit, the method comprising:

• arbitrating between requests to access a bus by a first bus master and one or more other bus masters;
• receiving a restrict bus access signal, by the digital processing circuit, a predetermined amount of time prior to the RF circuit changing to an adaptive mode, wherein during the predetermined amount of time, the first bus master obtains access to the bus and performs perform necessary pre-shut-down tasks prior to the digital processing circuit shutting down;
• and
• shutting down the digital processing circuit at the end of the predetermined amount of time, for a window of time, while the RF circuit operates in an active mode.

A mobile phone comprising:

• a radio frequency (RF) transceiver adapted to operate a radio frequency signal;
• and
• a digital processing circuit coupled to the RF transceiver, wherein the digital processing circuit includes:
• a first bus master coupled to a bus;
• one or more other bus masters coupled to the bus;
• and
• a bus arbiter coupled to the bus and configured to arbitrate requests to access the bus by the first bus master and the one or more other bus masters;
• wherein access requests issued by the one or more other bus masters to access the bus are terminated in response to a restrict bus access signal asserted a predetermined amount of time prior to the RF transceiver operating on the radio frequency signal;
• wherein during the predetermined amount of time, the first bus master obtains access to the bus to carry out necessary pre-shut-down tasks prior to the digital processing circuit shutting down;
• and
• wherein the digital processing circuit shuts down at the end of the predetermined amount of time, for a window of time, while the RF transceiver operates on the radio frequency signal.

A mobile phone comprising:

• a radio frequency (RF) front-end circuit for operating on a radio frequency signal;
• a digital processing circuit coupled to the RF front-end circuit, wherein the digital processing circuit includes a first bus master coupled to a bus and one or more other bus masters coupled to the bus;
• and
• a bus arbiter coupled to the bus and configured to arbitrate between requests to access the bus by the first bus master and the one or more bus masters;
• wherein access requests issued by the one or more other bus masters to access the bus are denied in response to a signal asserted for a predetermined amount of time prior to the RF front-end circuit operating on the radio frequency signal;
• wherein during the predetermined amount of time, the first bus master is adapted to obtain access to the bus to perform necessary pre-shut-down tasks prior to the digital processing circuit shutting down;
• wherein the digital processing circuit shuts down at the end of the predetermined amount of time, for a window of time, while the RF front-end circuit operates on the radio frequency signal;
• and
• wherein the RF front-end circuit and the digital processing circuit are fabricated on a signal integrated circuit chip.

A communication apparatus comprising:

• a radio frequency (RF) circuit adapted to operate on a radio frequency signal during a window of time;
• and
• a digital processing circuit coupled to the RF circuit, wherein the digital processing circuit includes:
• a first bus master coupled to a bus;
• one or more other bus masters coupled to the bus;
• and
• a bus arbiter configured to arbitrate between requests to access the bus by the first bus master and the one or more other bus masters;
• wherein accesses requests issued by the one or more other bus masters to access the bus are denied by the bus arbiter in response to a signal asserted for a predetermined amount of time prior to the RF circuit operating on the radio frequency signal;
• wherein during the predetermined amount of time, the first bus master is adapted to access the bus to perform necessary digital processing circuit pre-shut-down tasks;
• and
• wherein the digital processing circuit is adapted to enter a shutdown mode at the end of the predetermined amount of time, for the window of time, while the RF circuit operated on the radio frequency signal.

A communication apparatus comprising:

• a radio frequency (RF) circuit adapted to be activated for operating on a radio frequency signal during a radio active mode and be inactive during a radio inactive mode;
• and
• a digital processing circuit coupled to the RF circuit, wherein the digital processing circuit includes:
• a first bus master coupled to a bus;
• one or more other bus masters coupled to the bus;
• and
• a bus arbiter configured to arbitrate between requests to access the bus by the first bus master and the one or more other bus masters according to an arbitration policy during at least a portion of a duration of the inactive mode of operation of the RF circuit;
• wherein the bus arbiter is further configured to implement a less favorable arbitration policy for the one or more other bus masters in response to a signal asserted a predetermined amount of time prior to an end of the duration of the inactive mode of operation of the RF circuit;
• and
• wherein during the predetermined amount of time, the first bus master obtains access to the bus to perform necessary tasks prior to the digital processing circuit shutting down at the end of the duration of the inactive mode for a window of time, during which the RF circuit is activated for operating on the radio frequency signal.

A mobile phone comprising:

• a radio frequency (RF) transceiver adapted to operate on a radio frequency signal;
• and
• a digital processing circuit coupled to the RF transceiver, wherein the digital processing circuit includes:
• a first bus master coupled to a bus;
• one or more other bus masters coupled to the bus;
• and
• a bus arbiter configured to allow accesses to the bus by the first bus master and the one or more other bus masters according to an arbitration policy implemented during a first period of operation;
• wherein accesses requests issued by the one or more other bus masters to access the bus are restricted during a second period of operation in response to a restrict bus access signal asserted a predetermined amount of time prior to the RF transceiver operating on the radio frequency signal for a third period of operation;
• wherein during the predetermined amount of time, the first bus master is adapted to obtain access to the bus and to perform necessary digital processing circuit pre-shut-down tasks;
• and
• wherein the digital processing circuit is adapted to shut down at the end of the second period of operation, for the third period of operation, while the RF transceiver operates on the radio frequency signal.