SIS Documentation
SIS3153
VME interface
Page 15 of 38
(*3) if Switch SW162-7 is ON and VME_SYSRESET bit is set then VME_SYSRESET is
issued
(*4) A retry error (error code 0x212) may be caused by older VME backplanes, which do not
properly terminate this previously reserved (pin B3 on connector P2) if retry is enabled.
Retry can be disabled by setting bit 24. Retry had to be activated by setting bit 8 on the
SIS3153, this behaviour is not compatible with SST transfers.
(*5) Setting bit 10 causes the SIS3153 to release busy for 170 ns in between of blockletts
during a block transfer. This gives another master the possibility to gain busmastership
during the block transfer. The SIS3153 will terminate the block transfer with an
arbitration timeout if the other master does not release busmastership within the long
timer period. The AS-AS gap of 90 ns will be extended by the 170 ns release period, i.e.
the reduction in transfer speed is negligible.
Explanation/function of bit combinations:
SYSTEM VME BERR TIMER BIT1
SYSTEM VME BERR TIMER BIT0
VME Bus Error after
0
0
1,25
s
0
1
6,25
s
1
0
12,5
s
1
1
100
s (default)
Note:
The default value of 1,25
s will be fine with most of VME slaves on the market, there are peculiar cards
which will respond to a VME cycle much slower however also. The bus error code is 0x211.
LONG TIMER BIT1
LONG TIMER BIT0
LONG Timeout after
0
0
1 ms (default)
0
1
10 ms
1
0
50 ms
1
1
200 ms
LONG Timeout: arbitration timeout, no reply from current VME master or VME bus mastership not granted
The arbitration timeout error code is ox214.
VME_REQ_LEVEL BIT1
VME_REQ_LEVEL BIT0
VME Bus Request Level
0
0
BR3 (highest Level, default)
0
1
BR2
1
0
BR1
1
1
BR0
VME REQUESTER TYPE BIT
VME Bus Requester Type
0
Release when Done (default)
1
Release on Request
