M41T81REG_SC
m41t81_write(M41T81REG_SC, tm.tm_sec);
sec = m41t81_read(M41T81REG_SC);
if (sec == m41t81_read(M41T81REG_SC)) break;
tmp = m41t81_read(M41T81REG_SC);
m41t81_write(M41T81REG_SC, tmp & 0x7f);
return m41t81_read(M41T81REG_SC) != -1;