QS_CCT_CTR0
writeb(QS_CTR0_REG, chan + QS_CCT_CTR0);
readb(chan + QS_CCT_CTR0); /* flush */
readb(chan + QS_CCT_CTR0); /* flush */
writeb(QS_CTR0_CLER, chan + QS_CCT_CTR0);
writeb(QS_CTR0_REG, chan + QS_CCT_CTR0);
readb(chan + QS_CCT_CTR0); /* flush */