Digital audio interface in a mobile telephone

• US 5,490,235 A
• Filed: 01/24/1994
• Issued: 02/06/1996
• Est. Priority Date: 10/03/1991
• Status: Expired due to Term

• Current Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Von Holten, Arnold, Kolehmainen, Timo
• Primary Examiner(s): MacDonald, Allen R.
• Assistant Examiner(s): Doerrler, Michelle
• Application Number:
  US08/185,769
• Time in Patent Office: 743 Days
• Field of Search: 380/28-33, 371/22.1-22.6, 324/120, 395/2.1, 395/2.79
• US Class Current: 704/270
• CPC Class Codes: H04M 1/24 Arrangements for testing
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements

Abstract

A GSM mobile telephone includes a digital audio interface for interfacing with a system simulator for test purposes. A digital signal processor within the mobile telephone includes a codec data register that interfaces to an analog codec which provides A/D and D/A conversion of speech signals. An interface circuit is connected to the codec data register and includes a digital audio interface block and a test access port data register, both of which enable test data inputs and test data outputs to be respectively fed to the mobile telephone'"'"'s digital signal processor and enable test functions to be accomplished without a requirement for loading of test program into the mobile telephone station.

Claims

1. A mobile telephone station comprising:

a digital signal processor (DSP) for coding and decoding speech signals and including a codec data register;

an analog codec coupled by an electrical circuit to said codec data register, for converting digital speech signals received from said codec data register in said DSP to analogue speech signals and for converting received analogue speech signals to digital speech signals and for feeding said digital speech signals to said codec data register in said DSP, said electrical circuit comprising a first circuit for coupling signals from said analog codec to said DSP and a second circuit for coupling signals from said DSP to said analog codec; and

an interface circuit connected in parallel with said analog codec and to said electrical circuit, said interface circuit having inputs connected to said first circuit and second circuit and outputs connected to said first circuit and second circuit, said interface circuit including a digital audio interface block that is connectable to a system simulator and furthermore including a test access port data register coupled to said digital audio interface block and further connected to said electrical circuit between said digital audio interface block and said codec data register, whereby test data inputs and test data outputs are respectively fed to said mobile telephone station via said digital audio interface block and test access port data register from a connected system simulator, without a requirement for loading of a test program into said mobile telephone station.

2. The mobile telephone station as recited in claim 1, wherein said DSP includes plural commands which implement reading and writing procedures for data contained in said test access port data register.

3. The mobile telephone station as recited in claim 2, wherein said plural commands are loaded into said DSP from a said system simulator via said test access port data register.