han's logs at JLab

F1 TDC

For Normal Resolution and Synchronous mode, we need to change only Registers 7, 8, 9, and 10 and we can use the default configurations as follows:

Register  0 : 0180
Register  1 : 0000
Register  2 : 4040
Register  3 : 4040
Register  4 : 4040
Register  5 : 4040
Register  6 : 0000
Register  7 : C880
Register  8 : 63A4
Register  9 : CDEC
Register 10 : 1FBC
Register 11 : 0000
Register 12 : 0000
Register 13 : 0000
Register 14 : 0000
Register 15 : 000C

• Register 7 bits 6-14 : Interval (tframe) between start signals (refcnt : reference starter counter)

 
   tframe = ( refcnt + 2 ) * Tref
   refcnt = tframe / Tref - 2

• Register 8  : Trigger window width (trigwin)

   
trigwin < 0.9 * tframe

• Register 9 : Trigger window latency or offset (triglat)

  
 triglat < 0.4 * tframe

• Register 10 : Resolution (bin size) of the F1TDC by setting the reference clock divider(refclkdiv) and the high speed divider(hsdiv)

   
   # bits 8-10 : refclkdiv (possible factor 1,2,4,...128) 2refclkdiv
   # bits 0- 7 : hsdiv, 0 - 255

Thus, resolution is

 
Resolution  = Tref * 2refclkdiv / (152*hsdiv), where Tref = 25 ns (by clock 40 MHz)  

• decide the resolution (bin size)

 resolution [ns] = 25  * 2refclkdiv / (152*hsdiv) >>> Register 10 bits 0-10

• decide the tframe

 tframe = ( refcnt + 2 ) * 25
 refcnt = tframe / 25 - 2 >>>  Register 7 bits 6-14 

• decide the window width (ns)

  window [ns] = trigwin * resolution 
  trigwin = window / resolution  < 0.9 * tframe >>> Register 8 

• decide the latency (ns)

 latency [ns] = triglat * resolution 
 triglat = latency / resolution < 0.4 * fframe >>> Register 9 

• Using resolution, we can calculate "full_range"

 full_range = 65536 * resolution 

• T_ref : 25 ns (40 MHz Reference Internal Clock)
• refcnt : Reference Start Counter (Register 7 bits 6-14)
• tframe : Start interval or restart period (interval between start signals)
• refclkdiv : Reference Clock Divider (Register 10 bits 8-10)
• hsdiv : High Speed Divider (Register 10 bits 0-7)
• trigwin : Trigger Window
• triglat : Trigger Window Latency or Offset