vT1CH
via_reg(VIA1, vT1CH) = CLK_INTH;
via_reg(VIA2, vT1CH) = (profint - 1) >> 8;
via_reg(VIA2, vT1CH) = 0;
via_reg(VIA1, vT1CH) = 4; /* (approx 1.3 msec) */
via_reg(VIA1, vT1CH) = 0;
via2_reg(vT1CH) = 0;