Convert ticks from hardware timestamp

When getting the hardware timestamp, the higher resolution part is measured in ticks and a conversion based on the nominal clocks is done to convert to user units
PandABlocks · Feb 15, 2024 · 6c95ae6 · 6c95ae6
1 parent 1889c83
commit 6c95ae6
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Showing 3 changed files with 7 additions and 6 deletions.
diff --git a/config_d/registers b/config_d/registers
@@ -42,7 +42,7 @@ BLOCKS_COMPAT_VERSION = 0
 
     # Hardware timestamps
     PCAP_TS_SEC             10
-    PCAP_TS_NSEC            11
+    PCAP_TS_TICKS           11
 
     # Position capture control
     PCAP_ARM                13

diff --git a/server/data_server.c b/server/data_server.c
@@ -122,11 +122,9 @@ static void update_start_timestamp(void)
         pcap_start_ts = pcap_drv_start_ts;
         pcap_hw_ts_offset_ns_valid = false;
     } else {
-        int64_t drv_ts_num =
-            (int64_t) pcap_drv_start_ts.tv_sec * 1000000000
+        int64_t drv_ts_num = (int64_t) pcap_drv_start_ts.tv_sec * NSECS
             + pcap_drv_start_ts.tv_nsec;
-        int64_t hw_ts_num =
-            (int64_t) pcap_hw_start_ts.tv_sec * 1000000000
+        int64_t hw_ts_num = (int64_t) pcap_hw_start_ts.tv_sec * NSECS
             + pcap_hw_start_ts.tv_nsec;
         pcap_start_ts = pcap_hw_start_ts;
         pcap_hw_ts_offset_ns = drv_ts_num - hw_ts_num;

diff --git a/server/hardware.c b/server/hardware.c
@@ -328,7 +328,10 @@ void hw_get_start_ts(struct timespec *ts)
 void hw_get_hw_start_ts(struct timespec *ts)
 {
     ts->tv_sec = (time_t) read_named_register(PCAP_TS_SEC);
-    ts->tv_nsec = (typeof(ts->tv_nsec)) read_named_register(PCAP_TS_NSEC);
+    ts->tv_nsec = (typeof(ts->tv_nsec)) ((double)
+        read_named_register(PCAP_TS_TICKS) * NSECS / hw_read_nominal_clock());
+    ts->tv_sec = ts->tv_nsec / NSECS;
+    ts->tv_nsec = ts->tv_nsec % NSECS;
 }
 
 #endif