BRSRC
wr(scc, R14, BRSRC); /* BRG source = PCLK */
write_zsreg(uap, 14, (LOOPBAK | BRSRC));
write_zsreg(uap, 14, (LOOPBAK | BRSRC | BRENAB));
up->curregs[R14] = BRSRC | BRENAB;
up->curregs[R14] = BRSRC | BRENAB;
BRSRC | BRENABL, /* write 14 */