SEQUENCE OF OPERATIONS

                             FROM TEST-LOGIC-RESET

                     (BOTH SWITCHES SET TO DIGITAL POSITION)



            TEST SYSTEM                                DEVICES(S)

 -SCAN IN ANALOG SETUP INSTRUCTION
                                              -SELECT ANALOG CONTROL REGISTER
 -SCAN IN BITS FOR ANALOG CONTROL
    INCLUDING NUMBER OF ANALOG STEPS
                                              -ACCEPT, SHIFT, ETC.
 -SCAN IN ANALOG EXECUTE INSTRUCTION
                                              -SELECT "D-REGISTER"
 -STEP ALL TAPS TO SHIFT-DR, STOP
    WITH TCK, TMS, TDO = 0
                                              -ENABLE TDO (ZERO RIPPLES)
                                              -FORCE ZERO AT TAP CONTROLLER
                                                  TCK, TMS INPUTS
                                              -SET SWITCH TO ANALOG
                                              -WAIT FOR TDI TOGGLE
 -WAIT FOR RIPPLE COMPLETION
 -SET SWITCH TO ANALOG
 -TOGGLE TDO                       ____________
                                              -ENABLE SET OF ANALOG MATRIX
                                                  CONNECTIONS FOR STEP (ACR)
                                              -WAIT FOR TDI TOGGLE
 -MAKE ANALOG MEASUREMENT           REPEATED
    IF NEEDED                      FOR EACH
 -IF LAST STEP, SET SWITCH TO       STEP PER
    DIGITAL, SET TCK, TMS = 0      ACR LOAD
 -TOGGLE TDO
                                  ____________
                                              -DISABLE ANALOG MATRIX
                                              -SET SWITCH TO DIGITAL
                                              -OBSERVE TCK, TMS NORMALLY
 -RESUME DIGITAL OPERATIONS



_____________________________________________________________________

                        (REFERENCE 1/16/96 EMAIL DIAGRAM)

                       4 WIRE MIXED SIGNAL JTAG TEST METHOD

                                                              RJR 2/7,8/96