Clocking-and-synchronisation.md

@@ -12,6 +12,8 @@ In normal operation mode (register settings `EnPLL = 1` and `SelEx = 0`.), we ob
 * For an input clock of `X Mhz`, the precision of the first timestamp (TS1) is `(1+ckdivend1)*2000/X ns`  (ex: `80MHz, ckdivend1=0 -> 25 ns`), where `ckdivend1` is the clock divider register for TS1
 * For an input clock of `X Mhz`, the precision of the first timestamp (TS2) is `(1+ckdivend2)*1000/X ns`  (ex: `80MHz, ckdivend2=0 -> 12.5 ns`), where `ckdivend2` is the clock divider register for TS2
 
+By default, the ATLASPix input clock is set at 80 MHz. A new firmware version is needed if you want to use other clock speed
+
 
 # Synchronisation