In the system of Figure 10-33, A, B, and C are BILBO registers. The B₁and B₂inputs to each of the registers determine its BILBO operating mode as follows:
B₁B₂= 00, shift register; B₁B₂= 01, PRPG (pattern generator); B₁B₂= 10, normal system mode; B₁B₂= 11, MISR (signature register). The shifting into A, B, and C is always LSB first. When in the test mode, the Dbus is not used. Specify the sequence of the tester outputs (B₁, B₂, and S_i) needed to perform the following operations:

1. Load A with 1011 and B with 1110; clear C.
2. Test the system by using A and B as pattern generators and C as a signature register for four clock times.
3. Shift the C register output into the tester.
4. Return to the normal system mode. 

B₁ B₂ S_i = 0 0 0,

Figure 10-33: System with BILBO Registers and Tester

Transcribed Image Text:

System | Dbus Scan path LdA Test LdC 4 CE TestD CE B1 B2 Carry 4. LdB Test Adder Sum CE B1 B, B1 B2 So B1 B2 Si Tester