Overview
The SCANSTA112VSX/NOPB, produced by Texas Instruments, is a 7-port multidrop IEEE 1149.1 (JTAG) multiplexer. This device extends the IEEE Std. 1149.1 test bus into a multidrop test bus environment, enhancing test throughput and allowing for the removal of a board from the system while retaining test access to the remaining modules. It supports up to 7 local IEEE 1149.1 scan chains, which can be accessed individually or combined serially, and is particularly useful in board-level management of multiple scan chains and in multidrop addressable backplane configurations.
Key Specifications
| Parameter | Value |
|---|---|
| Package | TQFP (NEZ) - 100 pins |
| Operating Temperature Range | -40°C to 85°C |
| Supply Voltage (VCC) | 3.0V to 3.6V |
| Input Voltage (VI) | 0V to VCC |
| Output Voltage (VO) | 0V to VCC |
| Maximum Quiescent Supply Current (ICC) | 3.8 mA |
| Maximum Dynamic Supply Current (ICCD) | 68 mA at 25MHz |
| Propagation Delay (tPHL, tPLH) | 7.5 ns to 14.0 ns |
Key Features
- True IEEE 1149.1 Hierarchical and Multidrop Addressable Capability
- 8 Address Inputs supporting up to 249 unique slot addresses, an interrogation address, broadcast address, and 4 multi-cast group addresses
- 7 IEEE 1149.1-compatible configurable local scan ports
- Bi-directional backplane and LSP0 ports that are interchangeable slave ports
- Capable of ignoring TRST of the backplane port when it becomes the slave
- Stitcher mode bypasses level 1 and 2 protocols
- Mode register allows local TAPs to be bypassed, selected for insertion into the scan chain individually, or serially in groups of two or three
- Transparent mode can be enabled with a single instruction to buffer the backplane IEEE 1149.1 pins to those on a single local scan port
- General purpose local port pass-through bits for delivering write pulses for flash programming or monitoring device status
- Known power-up state with TRST on all local scan ports
- 32-bit TCK counter and 16-bit LFSR signature compactor
- Local TAPs can become TRI-STATE via the OE input to allow an alternate test master to take control of the local TAPs
- Supports live insertion/withdrawal
Applications
The SCANSTA112VSX/NOPB is primarily used in various testing and programming applications, including:
- Board-level management of multiple scan chains to improve fault isolation, reduce test times, and minimize vector sets.
- Multidrop addressable backplane environments where multiple IEEE 1149.1 accessible cards can utilize the same backplane test bus for system-level access.
- Structural test and programming throughout the entire system life cycle.
- Hierarchical boundary-scan tree configurations, allowing selective communication with specific portions of a target system.
Q & A
- What is the primary function of the SCANSTA112VSX/NOPB?
The primary function is to extend the IEEE Std. 1149.1 test bus into a multidrop test bus environment, enhancing test throughput and flexibility.
- How many local IEEE 1149.1 scan chains can the SCANSTA112VSX/NOPB support?
It supports up to 7 local IEEE 1149.1 scan chains.
- What is the operating temperature range of the SCANSTA112VSX/NOPB?
The operating temperature range is -40°C to 85°C.
- What is the supply voltage range for the SCANSTA112VSX/NOPB?
The supply voltage range is 3.0V to 3.6V.
- Can the backplane and LSP0 ports be configured as master or slave ports?
- What is the purpose of the 32-bit TCK counter?
The 32-bit TCK counter enables built-in self-test operations to be performed on one port while other scan chains are simultaneously tested.
- Does the SCANSTA112VSX/NOPB support live insertion/withdrawal?
- How many unique slot addresses can be supported by the 8 address inputs?
The 8 address inputs support up to 249 unique slot addresses, along with an interrogation address, broadcast address, and 4 multi-cast group addresses.
- What is the purpose of the transparent mode in the SCANSTA112VSX/NOPB?
The transparent mode can be enabled with a single instruction to conveniently buffer the backplane IEEE 1149.1 pins to those on a single local scan port.
- Can the local TAPs become TRI-STATE to allow an alternate test master to take control?
