SSN Slang Glossary

To address the traditional SCAN technology's sustainability pain points, SSN has created a lot of new concepts that does not exist before and a lot of acronyms along with them. The purpose of this cheat sheet is supposed to help users who are new to SSN to understand the slang that we speak.

Platform agnostic terms

Accumulated Status

• refer to On-Chip Compare
• Per-shift pass/fail status bits accumulated​ across all ssh_icl_instances of the same capture_global_group

capture_global_group

• refer to representative_ssh
• ssh_icl_instances that share the same capture_global_group ID appear as only one ssh_icl_instance on the ssn bus.

Contribution Bits (disable_contribution_bit)

• A RW bit, if asserted (set to 1), that can prevent a ssh_icl_instance's On-Chip compare logic to modify(contribute) the Accumulated Status slots.
• refer to On-Chip Compare.

core_instance

• A core is often a function IP with established EDT networks.
• It can be assigned with one ssh instance or multiple if the core is too complex.
• you can consider a core instance as a group of ssh_icl_instances, note that the group may only contains one ssh_icl_instance.
• when testing, core instance need to be tested as a minimum unit. which means all ssh_icl_instances of a given core instance need to be enabled.

EDT

• Embedded Deterministic Test

ICL (icl)

• Instrument Connectivity Language

iJTAG

• IEEE 1687

On-Chip Clock (OCC)

• this is to highlight that OCC is typically referring to On Chip Clock, while On-Chip Compare uses OCComp

On-Chip Compare (OCComp)

• A ssh takes its scan in data as well as scan out data (expected and masked) from predictable preallocated time slot on the ssn bus and offload the mis-compares on a dedicated region on the preallocated time slot called accumulated status zone.

• Per-shift pass/fail status bits accumulated​ across ssh_icl_instances (SSN stream)
• Sticky pass/fail status bit per ssh_icl_instances (IJTAG)

• refer to Sticky Bits

representative_ssh

• when multiple identical ssh_icl_instances are tested simultaneously as a group, they can share the same scan in data & scan out expected/mask data. In that case, only one copy of the data is present on the ssn bus and one bucket of time slots will be allocated. Siemens use the first appeared ssh_icl_instance in that group as the representative ssh, whose name will appear in the pin/cycle-to-ssh mapping section, and for the following appeared ssh_icl_instances they will have an attribute that points to the first ssh, namely representative ssh.
• representative ssh represent a group of ssh_icl_instances that share the same capture_global_group ID with it.
• User can't tell if a ssh_icl_instance from the mapping section is a representative_ssh or not.
• User need to parse the Active Ssh Section to get that information.

SMux

• A Multiplexer on the ssn Bus

SSH (ssh)

• Streaming Scan Host

ssh_icl_instance

• an instance of an ssh, accessed via iJTAG with a unique icl address.
• in most cases the term ssh instance and icl instance are interchangeable, so it may be referred to as ssh_icl_instance in the mapping section of a pattern(stil) file.

SSN

• Streaming Scan Network

Sticky Bits (sticky_bit)

• A RO bit, if asserted (set to 1), that marks the failure status of a ssh_icl_instance's On-Chip compare logic since last reset. ( a reset is typically done in ssn_setup or ssn_end)
• refer to On-Chip Compare

Tester Compare (TC)

• A ssh takes its scan in data from predictable preallocated time slot on the ssn bus and offload the EDT's scan out data on the same time slot.

• each time slot on the ssn bus out will map to a ssh_icl_instance (or a group of identical ssh_icl_instance that share the same representative ssh)

• tester will compare the scan out against the expected and any mis-compare will map to the ssh_icl_instance, thus one will know which ssh_icl_instance failed and which core instance failed.

Pattern Related

ssn_setup pattern

• the pattern for setting up the ssn bus and active ssh instances
• it configs all the disable_contribution_bit of active ssh instances
• only the JTAG port is active, the ssn bus is in idle state

ssn_payload pattern

• the pattern that contains all the streaming scan data
• the scan blocks are packed back-to-back without parallel vectors in between
• JTAG and other control pins are in idle state.
• this type of pattern should contain an attribute called atpg_scan_network, it's a reference pointing to the ssn_mapfile.csv

ssn_end pattern

• the pattern for resetting the ssn bus and active ssh instances
• it also collect the status of all sticky_bits
• only the JTAG port is active, the ssn bus is in idle state

*_ssn.csv

• a file that is generated along with the ssn_setup pattern or the ssn_end pattern
• contains the extracted active ssh instances information
• the content is subject to change due to the evolution of ssn
• IG-XL currently(as of 11.0) do NOT parse the file, a code lib provided by Factory Apps will read and parse the file.

*_ssn_mapfile.csv

• a file that is generated along with the ssn_payload pattern.
• contains the information of pin/cycle-to-core(ssh) mapping
• the content is subject to change due to the evolution of ssn
• IG-XL will parse and load the file while loading the payload pattern.

cycle_repetition

• fitting a N bit streaming packet data on a M bit wide bus will result in the mapping pattern to repeat every R cycle, where R = LCM(M, N) / M
  • LCM: Least Common Multiple
• it means every R cycles the pin/cycle-to-core(ssh) mapping relation repeats.
  • for each scan out pin, the cycle-to-core(ssh) mapping repeats every R cycles
• we call the R cycle_repetition
• refer to cycle_modulo

cycle_modulo

• refer to cycle_repetition
• with the mapping being cycling, a given modulo number on a given pin will constantly map to a fixed core
• the mapping table is constructed with 4 columns being:
  • pin
  • cycle_repetition
  • cycle_modulo
  • core/ssh-icl instance

rotation

• fitting a N bit streaming packet data on a M bit wide bus will result in the mapping pattern to repeat every R cycle, where R = LCM(M, N) / M
  • LCM: Least Common Multiple
• sometimes user would patch the streaming data so that N is integer multiple of M, this is called rotation = off
• the most efficient way is to disable patching, which is called rotation = on
• refer to cycle_repetition
• refer to cycle_modulo

prime_scan_mask (opcode)

• a opCode that is needed for masking core/ssh-icl instance.
• refer to prime_scan_mask, prime_no_scan_mask