SIS Documentation
SIS3820
VME Scaler
Page 68 of 79
15.7 Histogramming Scaler (HISCAL)
Histogramming scalers are typically used for repetitive low count rate applications. While the
VME master has to readout the data across the VME bus in MCS mode, counts from
consecutive scans are added up on board the SIS3820 in HISCAL operation.
HISCAL operation is the combination of MCS mode with SDRAM add mode. The
HISCAL_START signal is used in addition to the MCS setup. The HISCAL_START signal
(from VME or as a front panel input, as defined with the HISCAL_START_SOURCE_BIT of
the operation mode register) resets the memory pointer to the beginning of the histogram
(until the HISCAL_START_PRESET value is reached or HISCAL operation is disabled.
Refer to the 3 histogramming scaler Visual C++ examples to get started.
15.7.1 Minimum dwell time in HISCAL mode
Find below a table with minimum dwell times for 2 configurations in HISCAL mode.
Number of channels Channel depth (bits) Dwell time in ns
32 32
4000
... ...
...
4 32
500
Note:
High word count block transfer access to the SDRAM in parallel to MCS/HISCAL
acquisition can result in an increased worst case minimum dwell time of some 8 µs.
15.8 Firmware upgrade over VME
SIS3820 units at firmware greater or equal 0102 support firmware upgrade over the VME
bus. The VME to JTAG interface is implemented through the JTAG_TEST/JTAG_DATA_IN
and the JTAG_CONTROL registers. Refer to the documentation for the XILINX XC18V04
serial PROM for operation details.
The LINUX and Visual C++ sis3820_jtag_prom.c code on the CDROM allows you to
upgrade the firmware of your SIS3820 in combination with the SIS1100/3100 PCI to VME
interface or to port the code to your VME environment.
Note 1:
select the proper JP570 jumper setting to activate JTAG over VME
Note 2:
A SIS3820 module may be rendered in non working condition after an error in the
firmware download sequence. Operation/proper firmware has to be re-established with a
JTAG firmware download cable in that case.