User guide

10.2.2 Inbound Scatter-Gather Entries
The inbound scatter-gather RAM format is shown in Figure 10–9 and described
in Table 10–3.
Figure 10–9 Inbound Scatter-Gather Entry With A32 Address Mapping
31 08 06 05 04 00
ML013342
Inbound Scatter-Gather Page Monitor
I/O Select
Memory Page
Supervisor Access Only
Write Lock
Valid
VME Addr <26:13>
091011121314
MBZ
31 02 01 00
Memory Page
Memory Addr <31:0>
00
VME Addr <12:2>
Swap
1213
0
Table 10–3 VME Address
Field Name Description
<4:0> MBZ
<5> Valid
<8:6> Swap
<9> Write Lock Limits slave accesses to read-only, that is, a page can be
write-locked.
<10> Supervisor
Access Only
Restricts access to supervisory cycles only.
<11> PCI I/O Mem
Select
When clear (the default), the VME master uses a PCI memory
cycle to transfer VME data to the mapped main memory
address. When set, it forces a PCI I/O cycle to allow a VME
device access to one of Digital Alpha VME 4 system’s I/O
resources.
(continued on next page)
10–12 VME Interface