TDC-GPX datasheet(49/54 Pages) AMSCO

49 / 54 page

TDC-GPX

acam-messelectronic gmbh - Am Hasenbiel 27 - D-76297 Stutensee-Blankenloch - Germany - www.acam.de

2. Apply Start and Stop signals with a short delay (e.g.

12ns)

3. Step down the interval and look at the output data.

They are getting smaller and smaller until you pass

the internal Start time stamp. The output data then

jumps to a very high value.

4. Take the time interval tcross (from your generator)

where this happens

5. Calculate StartOff1 = tcross / BIN and write this

value into register 5, StartOff1. In case you expect

negative values add an additional amount X to Star-

tOff1 and substract this value later on from your

output data

Internal Data Processing

The raw values of the stop events are stored in the Hit

FIFOs.

The following pipelined post-processing unit is respon-

sible for compression, Start selection and correct

Stop-Start subtraction. Subsequently a collection unit

transfers the data to the Interface FIFOs. Each channel

has its own interface FIFO. The maximum rate for

transfer into the Interface FIFO is 40 MHz.

Finally a data multiplexer adds data from both Inter-

face FIFOs to the data bus. The data bus is 28 Bits

wide and capable of 40 MHz transfer rate. The data

bus can be switched to 16 Bit width writing

0x0000010 into address 14. A LOW at pin ‘Output

enable’ forces the bidirectional bus drivers to perma-

nent output state. This is helpful for fast data read out

routines.

Each Interface FIFO has an empty flag (EF) and a load-

level flag (LF). All flags are HIGH active. At low data

rates it is recommended to check the EF to see

whether there are data available for read out. It is not

allowed to read from an empty Interface FIFO. The LF

is helpful at high data rates. The load level threshold

can be set in ‘Fill’ in register 6 and is the same for

both FIFOs. As soon as the set number of data is avail-

able this can be read from the FIFO as a block without

the need of checking the EF.

Note: the load-level flags are not synchronized. The

load-level flag for a FIFO is valid only if it is not read

from this FIFO. Otherwise there might be spikes.

Quiet Mode

In M-Mode it is mandatory to use the Quiet mode.

In Quiet Mode the post-processing and calculation

does not start automatically after each single event,

but after a dedicated trigger. The trigger can be given

externally by a rising slope at pin ALUTRIGGER or by

software setting a dedicated ALU-Trigger Bit.

The time needed from the start of the post-processing

until first data is available in the interface FIFO is typ.

900 ns.

5.4 Data structure and readout

The output results are integers with a LSB width de-

fined by the setting of the resolution adjust unit, di-

vided by MSet.

MSet

hsdiv

216

BIN

refclkdiv

ref

Bit 27 … 23

Bit 22...0

Not used

Edge-to-Start result of the ad-

dressed combined channel

The data can be read from address 8 for interface

FIFO1 and from address 9 for interface FIFO2.

5.5 Reset

There are 3 ways of resetting the device:

Power-up reset: a low signal at pin PURESN

resets the whole chip.

Master-Reset: this command resets everything

except the configuration registers. It can be done

by software writing to register 4. In non-quiet

mode MasterAluTrig in register 5 can be set to

‘1’. Then this command can be done also by a

HIGH at the Alutrigger input pin. In quiet mode

MasterOenTrig in register 5 can be set to ‘1’.

Then this command can be done also by a LOW at

the OEN input pin (only with OEN off).

Partial-Reset: this command resets everything

except the configuration registers and the Inter-

face FIFOs. It can be done by software writing to

can be done also by a HIGH at the Alutrigger in-

put pin. In quiet mode PartialOenTrig in register 5

can be set to ‘1’. Then this command can be done

also by a LOW at the OEN input pin (only with OEN

off).

After a Power-on reset or a Master reset it takes 40

ns before the Start and Stop inputs accept data.

After a Partial reset it takes 75 ns before the Start

and Stop inputs accept data.

Member of the ams Group

TDC-GPX Datasheet(PDF) 49 Page - ams AG

TDC-GPX Datasheet(HTML) 49 Page - ams AG

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Datasheet Download

Link URL