Overview
The SCANSTA112SM/NOPB, produced by Texas Instruments, is a 7-port multidrop IEEE 1149.1 (JTAG) multiplexer designed to extend the IEEE Std. 1149.1 test bus into a multidrop test bus environment. This device enhances test throughput and allows 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.
Key Specifications
| Parameter | Value |
|---|---|
| Package | NFBGA (NZD) with 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 Low Output Voltage (VOL) | 0.2 V (IOUT = +100 μA), 0.4 V (IOUT = +12 mA), 0.55 V (IOUT = +24mA) |
| Maximum TRI-STATE Leakage Current (IOZ) | ±5.0 μA |
| Maximum Quiescent Supply Current (ICC) | 3.8 mA |
| Maximum Dynamic Supply Current (ICCD) | 68 mA (Input Freq = 25MHz) |
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 SCANSTA112SM/NOPB is primarily used in board-level and system-level testing environments. It facilitates the partitioning of scan chains into manageable sizes and isolates specific devices onto separate chains, improving fault isolation, test times, and programming times. This device is particularly useful in multidrop backplane environments where multiple IEEE 1149.1 accessible cards can utilize the same backplane test bus for system-wide structural test and programming.
Q & A
- What is the primary function of the SCANSTA112SM/NOPB?
The primary function is to extend 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.
- What type of package does the SCANSTA112SM/NOPB come in?
The device comes in a NFBGA (NZD) package with 100 pins.
- What is the operating temperature range of the SCANSTA112SM/NOPB?
The operating temperature range is -40°C to 85°C.
- How many local IEEE 1149.1 scan chains can the SCANSTA112SM/NOPB support?
The device supports up to 7 local IEEE 1149.1 scan chains.
- What is the supply voltage range for the SCANSTA112SM/NOPB?
The supply voltage range is 3.0V to 3.6V.
- Can the backplane and LSP0 ports be configured as master or slave ports?
Yes, the backplane and LSP0 ports are bidirectional and can be configured to alternatively act as the master or slave port.
- 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 SCANSTA112SM/NOPB support live insertion/withdrawal?
Yes, the device supports live insertion/withdrawal.
- How does the device handle TRST on the local scan ports?
The device has TRST on all local scan ports and can ignore TRST of the backplane port when it becomes the slave.
- What is the benefit of using the SCANSTA112SM/NOPB in a multidrop backplane environment?
The benefit includes improved fault isolation, faster test times, faster programming times, and smaller vector sets, facilitating system-wide structural test and programming.
