Hochschule Kempten      
Fakultšt Elektrotechnik      
Microelectronics       Fachgebiet Elektronik, Prof. Vollrath      

Test vector creation for digital circuits

Cycle time [s]:
CTRL signals:
Input signals:
Input registers:
Output signals and registers:
Output signal and register names should start with x,to be able to compare xQ from a voltage source to Q generated by the circuit.

State table


Control signals are omitted. The values are comma separated. The output is separated by a semicolon.
If a comment is required, it needs a label COMMENT and is separated by a comma.

For all "input signals" and "Input registers" before the semicolon all possible combinations are generated.
Expected data "Output signals and registers" is set to '0'.



A command T;0,1,0,1;0,0,1,1; generates 4 vectors using columns TE, TDI, xTDO
The first vector is used as default values for other control pins.

Make sure that there are no empty lines (NaN in LTSPICE output values).
From the vector list LTSPICE PWL statements and IRSIM simulation statements are generated.

Clock is automatically generated with rising edge at the center of input vector.
Therefore expected logic data is earlier than real simulated propagation delayed data. Expected register data are earlier than simulated data being valid after rising clock at half cycle and propagation delay.

Waveform



LTSPICE Code



IRSIM Code


Documentation


Fill in comma separated input signal and register names.
Fill in Output signal and register names starting with an added x.
Push "Generate state table inputs and registers" to generate a prefilled vector list.
Adjust expected data according to your circuit.
If a scan chain is used it can be loaded with a line starting with a T.
Make sure there are no empty lines.
Push "Resolve T commands".
Push "Generate analysis request".
Check displayed waveforms and copy LTSPICE code to LTSPICE file.

IRSIM

Save IRSIM commands to a <irsim.cmd> file.
Tools, Simulation (Built-in), IRSIM: Simulate current cell
Load Stimuli: Tools, Simulation (Built-in), Restore Stimuli fronm Disk.
Display Stimuli: Window, Fill Window