SIS Documentation
SIS3820
VME Scaler
Page 57 of 79
11 Jumper settings/pinouts
The SIS3820 has 3 jumper fields and a JTAG connector.
Jumper field Function
J1
VME addressing mode
J90 Reset
behavior
JP570 JTAG
source
CON500 JTAG
connector
The first pin of the jumper fields is marked by a square pin on the solder side and an extra
frame on the silk screen of the component side.
11.1 J1
J1 is in charge of the VME addressing mode and SDRAM size selection. At this point in time
the user can select between rotary switch selected A32 addressing and geographical A32
addressing.. A closed position selects the corresponding function.
Function
EN_A32
reserved
EN_GEO
J1
SDRAM
The default setting for a 64 MB unit is EN_A32 closed and all other positions opened.
Following memory architectures are supported
Memory
size rows columns banks
64 MB
12
9
1
512 MB
13
10
2
Note:
An example to determine the architecture from the SPD can be found in the Visual C++
example sis3820_sdram_eeprom.c
11.2 J90
J90 controls the reset behavior of the SIS3820.
Function
reserved
connect VME reset to SIS3820 reset
reserved
J90
enable watchdog
The default setting is VME reset and enable watchdog closed and all other positions opened.
Note:
open the enable watchdog for firmware upgrades