Does the Attorney General have any grounds to prevent a defendant from testifying in his own behalf?

Defendant further attacks the validity of Evidence Code, section 788 on constitutional grounds, which is left unanswered in the Attorney General's brief. The first facet of this constitutional attack is that the section permits the introduction of non-relevant matters not probative of whether the truth is being spoken and highly prejudicial, thus violating fundamental standards of fair trial. The second facet is that a rule permitting the introduction of prior felony convictions on the issue of credibility places too great a penalty upon his right to testify in his own behalf, citing Griffin v. California (1965) 380 U.S. 609, 85 S.Ct. 1229, 14 L.Ed.2d 106 in support.