National Semiconductor SCANSTA111MTX/NOPB

The SCANSTA111MTX/NOPB, produced by National Semiconductor (now part of Texas Instruments), is an Enhanced SCAN Bridge designed to extend the IEEE Std. 1149.1 test bus into a multidrop test bus environment. This component is particularly useful in complex systems where multiple devices need to be tested efficiently. It supports hierarchical and multidrop addressing, allowing for improved test throughput and the ability to remove a board from the system while retaining test access to the remaining modules.

• True IEEE 1149.1 Hierarchical and Multidrop Capability: Extends the IEEE Std. 1149.1 test bus into a multidrop environment, improving test throughput and flexibility.
• Addressing Scheme: Supports up to 121 unique addresses, an interrogation address, a broadcast address, and 4 multi-cast group addresses, allowing selective communication with specific portions of a target system.
• Local Scan Port Network: Each device supports up to 3 local IEEE 1149.1-compatible scan ports that can be accessed individually or combined serially.
• State Machines: Includes a TAP-control state-machine, a 'STA111-selection state-machine, and local scan port configuration state-machines to manage the scan operations efficiently.
• Broadcast and Multi-cast Addressing: Allows simultaneous selection of all 'STA111s in a test network or selective grouping using multi-cast addresses, preventing bus contention.
• Level 2 Protocol Compliance: Compliant with IEEE Std. 1149.1 TAP protocol with additional features for multidrop environments.

• Testing Equipment: Ideal for complex testing environments where multiple devices need to be tested efficiently.
• Board-Level Testing: Useful in systems where boards need to be tested individually or in groups without disrupting the entire system.
• Multidrop Test Bus Systems: Suitable for hierarchical test bus environments where multiple layers of 'STA111 devices can be connected to form a multi-level scan hierarchy.

1. What is the primary function of the SCANSTA111MTX/NOPB?

   The primary function is to extend the IEEE Std. 1149.1 test bus into a multidrop test bus environment, enhancing test efficiency and flexibility.

2. What is the voltage supply range for the SCANSTA111MTX/NOPB?

   The voltage supply range is 3V ~ 3.6V.

3. How many local scan ports does the SCANSTA111MTX/NOPB support?

   It supports up to 3 IEEE 1149.1-compatible local scan ports.

4. What addressing capabilities does the SCANSTA111MTX/NOPB offer?

   It supports up to 121 unique addresses, an interrogation address, a broadcast address, and 4 multi-cast group addresses.

5. How does the broadcast addressing mode work?

   The broadcast address allows a tester to simultaneously select all 'STA111s in a test network, with each 'STA111's TDOB buffer always TRI-STATEd to prevent bus contention.

6. What is the purpose of the multi-cast addressing mode?

   The multi-cast addressing mode allows selective grouping of 'STA111s into one of four multi-cast groups, enabling more targeted testing.

7. What state machines are included in the SCANSTA111MTX/NOPB?

   The device includes a TAP-control state-machine, a 'STA111-selection state-machine, and local scan port configuration state-machines.

8. How does the Level 2 Protocol work in the SCANSTA111MTX/NOPB?

   Once the 'STA111 is addressed and selected, its internal registers can be accessed via Level 2 Protocol, which is compliant with IEEE Std. 1149.1 TAP protocol with specific exceptions for broadcast and multi-cast modes.

9. What are the common applications of the SCANSTA111MTX/NOPB?

   Common applications include testing equipment, board-level testing, and multidrop test bus systems.

10. Is the SCANSTA111MTX/NOPB still in production?

    No, the production of the SCANSTA111MTX/NOPB has been discontinued by Texas Instruments.