diff --git a/Source/Doc/Architecture.md b/Source/Doc/Architecture.md
index d749cc52..ffc3120e 100644
--- a/Source/Doc/Architecture.md
+++ b/Source/Doc/Architecture.md
@@ -1721,6 +1721,7 @@ available along with the registers/information returned.
 |      _Returned Values_
 |           A: Status (0=OK, else error)
 |           DE:HL: Current Timer Tick Count Value
+|           C: Tick frequency (typically 50 or 60)
 
 #### SYSGET Subfunction 0xD1 -- Get Seconds Count (SECONDS)
 
diff --git a/Source/HBIOS/hbios.asm b/Source/HBIOS/hbios.asm
index 0f0fa77f..b4830d31 100644
--- a/Source/HBIOS/hbios.asm
+++ b/Source/HBIOS/hbios.asm
@@ -2458,6 +2458,7 @@ SYS_GETTIMER:
 	HB_DI
 	CALL	LD32
 	HB_EI
+	LD	C, TICKFREQ
 	XOR	A
 	RET
 ;