Patent ID: 8259231

Claim:
A portable navigation device (PND) with a TV function, comprising: a data bus; a TV module, coupled to the data bus, for receiving and processing a TV signal to generate a baseband TV signal; a navigation module, coupled to the data bus, for receiving and processing a satellite signal to generate position data; a display module, coupled to the data bus, for displaying an image associated with one of the baseband TV signal and the position data; a sound module, coupled to the data bus, for playing sound associated with one of the baseband TV signals and the position data; a general storage module, coupled to the data bus, for storing TV programs and TV data, and navigation programs and position data; a first processing unit, coupled to the data bus, for executing the navigation program to control the navigation module, the sound module, the display module, and the general storage module, and for generating a first TV command according to a TV enable signal; a second processing unit, coupled to the data bus, for executing the TV program to control the TV module, the sound module, the display module, and the general storage module, and for generating a second TV command according to a TV disable signal; a TV command storage module, coupled to the data bus, for storing the first TV command and the second TV command; a first interrupt controller, coupled to the first processing unit, for generating a first interrupt signal to the first processing unit according to the second TV command; and a second interrupt controller, coupled to the second processing unit, for generating a second interrupt signal to the second processing unit according to the first TV command; wherein the TV command strage module is a mailbox coupled to the data bus, the first interrupt controller and the second interrupt controller; wherein, when the first processing unit receives the TV enable signal, the first processing unit sends the first TV command to the mailbox via the data bus, the mailbox triggers the second interrupt controller to generate and to send the second interrupt signal to the second processing unit, and the second processing unit retrieves the first TV command stored in the mailbox; and when the second processing unit receives the TV disable signal, the second processing unit sends the second TV command to the mailbox via the data bus, the mailbox triggers the first interrupt controller to generate and to send the first interrupt signal to the first processing unit, and the first processing unit retrieves the second TV command stored in the mailbox.