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FADC progress in Vienna. Reported by H.Ishino for Vienna FADC group M.Pernicka and H.Steininger. Tests at Vienna Y.Ushiroda (KEK) H.Ishino (T.I.T.). Data transfer from FADC to PPCI Tests for cable cross talk Other topics related with FADC. Data transfer from FADC to PPCI.
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FADC progress in Vienna Reported by H.Ishino for Vienna FADC group M.Pernicka and H.Steininger
Tests at ViennaY.Ushiroda(KEK)H.Ishino (T.I.T.) Data transfer from FADC to PPCI Tests for cable cross talk Other topics related with FADC
Data transfer from FADC to PPCI • The data transfer was successfully done with the 10MHz clock. • However, with 20MHz we had a problem. • The first 32 bit datum which has a start bit was dropped, because the PPCI board needs 80nsec to be ready for receiving data. • To solve the problem, we dropped the first clock signal. • Data are transferred successfully. (we performed a long time test for about 12 hours. No error was detected.) • This may be a potential problem, i.e. a big external noise would cause read out error under real situation.
100nsec 10MHz clock Data 80nsec XVALID (FADC asserts) 50nsec 20MHz clock Data This datum is not valid
Read out test with a pulse generator trigger (1kHz) TTM ADC start FADC board Signal input A pulse generator 10bit FADC data PC (Linux7.1)
Checks for cross talk between twisted 30m cables Single shield Pair shield 5MHz clock signals One of twisted cables The other of the twisted cables Double shield No shield Differential of the twisted cables No cross talk was detected
FADC status The present Data format 32 bits 0th ADC 10 bits 0 1 0 ADC 10 bits 1 128/ch ADC 10 bits 127th 1 0 0 ADC 10 bits 1 Upper half part of FADC Lower half part of FADC Event counter from TTM (4 bits) We need not duplicate EV counter, start/stop bit. We requested to Vienna group to replace the one of EV and start/stop bit to channel # (4bit) and parity bit. Start bit (1 bit) Stop bit (1 bit)
FADC status The Data format we request 32 bits 0th ADC 10 bits 0 1 ADC 10 bits 128/ch ADC 10 bits 127th 1 0 0 ADC 10 bits 1 Upper half part of FADC Lower half part of FADC Channel # (4 bits) Event counter from TTM (4 bits) Start bit (1 bit) Parity bit (1 bit) Stop bit (1 bit)
L0 trigger L0 processor (Altera chip) was already mounted on a FADC board. The program which decides trigger issue by looking at combinations of TA outputs is being developed. If L0 processor issue trigger, a 50nsec width NIM signal and a 120nsec width ECL signal are generated. By Karawatzki-san (Vienna)
How the L1.5 trigger is implemented (outside of FADC) We need information of pedestal and noise levels to set a threshold level. Those levels are obtained from a sparcification process running on a PC which collects raw data from FADC boards. Write threshold levels to registers via VME bus FADC boards Raw data PC (Linux) Sparcification process Reduce data size and calculate noise and pedestal NSM (Network Shared Memory) Sparc board (CPU50?)
How often should we update the threshold levels? Right figures are time variations of noise and pedestal during a run (run#57, exp.17). pedestal noise Noise decreases by about 6%, while pedestal is almost stable. If we require 5% precision, we need to update the thr. Level one or two times during a run. This estimation came from SVD1.4. Of course the situation of SVD2.0 would be different. By Takeshita san (Osaka U)
Schedule of FADC Vienna group will send their system (FADC board, back board, VME crate and power supply) to KEK on middle of Mar. The full production of FADC boards will start on the end of April and finish on the end of July(?).
L1.5 trigger (inside of FADC) Registers for a threshold level of each channel have been prepared already. Reading/writing data from/to the registers via VME bus using a sparc CPU board was successfully done. The output signal of L1.5 trigger I am not sure for further more details about cable connection and so on. Ch 1 50nsec delay Ch 2 100nsec delay Ch 3 150nsec delay Ch 4 50nsec L1.5 output 20MHz clock