+#define CPM_DAY_OFFSET ((1978-1900) * 365 + 19) /* 19 leap years */
+
+/*
+ * Convert CP/M time stamp to a broken-down time structure
+ *
+ */
+int mk_date_time (int len, uint8_t *msg, struct tm *tmp)
+{
+ time_t stamp;
+
+ if (len != 5)
+ return -1;
+
+ /* days since 2000-01-01 */
+ long days = msg[3] + (msg[4] << 8) - 8036;
+
+ if (days < 0)
+ return -1;
+
+ stamp = days * ONE_DAY;
+ stamp += bcd2bin(msg[0]);
+ stamp += bcd2bin(msg[1]) * 60 ;
+ stamp += bcd2bin(msg[2]) * 3600L;
+ gmtime_r(&stamp, tmp);
+ return 0;
+}
+
+void mk_cpm_time(struct tm *tmp, uint8_t cpm_time[5])
+{
+ uint16_t days = 1;
+ uint_fast8_t leap=2;
+
+ for (int year=78; year < tmp->tm_year; year++) {
+ days = days + 365 + (leap == 0);
+ leap = (leap+1)%4;
+ }
+ days += tmp->tm_yday;
+
+ cpm_time[0] = bin2bcd(tmp->tm_sec);
+ cpm_time[1] = bin2bcd(tmp->tm_min);
+ cpm_time[2] = bin2bcd(tmp->tm_hour);
+ cpm_time[3] = days;
+ cpm_time[4] = days >> 8;
+}
+
+/* get/set cp/m time */
+void do_msg_get_set_time(uint8_t subf, int len, uint8_t * msg)
+{
+ struct tm t;
+ uint8_t cpm_time[5];
+ int rc;
+
+ memset(cpm_time, 0, ARRAY_SIZE(cpm_time));
+
+ switch (subf) {
+ case 3: /* set date & time */
+ /* initialize t with current time */
+ rc = rtc_get (&t);
+
+ if (rc >= 0) {
+ /* insert new date & time */
+ if (mk_date_time (len, msg, &t) != 0) {
+ my_puts_P(PSTR("## set_time: Bad date format\n"));
+ break;
+ }
+
+ time_t time;
+ time = mk_gmtime(&t);
+ gmtime_r(&time, &t);
+
+ /* and write to RTC */
+ rc = rtc_set (&t);
+ if(rc)
+ my_puts_P(PSTR("## set_time: Set date failed\n"));
+ } else {
+ my_puts_P(PSTR("## set_time: Get date failed\n"));
+ }
+ /* FALL TROUGH */
+ case 2: /* get date & time */
+ rc = rtc_get (&t);
+ if (rc >= 0) {
+ time_t time;
+ time = mk_gmtime(&t);
+ //mktime(&t);
+ gmtime_r(&time, &t);
+
+ mk_cpm_time(&t, cpm_time);
+ } else {
+ my_puts_P(PSTR("## get_time: Get date failed\n"));
+ }
+ break;
+ }
+
+ msg_xmit(3, subf, sizeof(cpm_time), cpm_time);
+}
+
+/* ---------------------------------------------------------------------------*/
+