Sun Microelectronics
153
8. Address Spaces, ASIs, ASRs, and Traps
Note:
Accesses to the UPA Port ID Register from the local processor return
undefined data. Similar state information can be accessed from the UPA
Configuration Register, described in Section 8.3.3.2, “UPA Configuration
Register,” on page 154.
Figure 8-1
UPA_PORT_ID Register Format
FC
16
:
A one byte field containing the value FC
16
. This is used by the open boot
PROM to indicate that no Fcode PROM is present for UltraSPARC.
ECC_Valid:
Cleared to zero since UltraSPARC can generate ECC when sourcing
data.
ONEREAD:
Set to zero. Although UltraSPARC can only support one outstanding
slave read S_REQ transaction at a time, it does not generate a P_RASB
reply.
PINT_RDQ:
Set to one, since one incoming P_INT_REQ transaction that may be
outstanding to UltraSPARC at a time.
PREQ_DQ:
Set to zero, since incoming slave data writes are not supported by
UltraSPARC.
PREQ_RQ:
Set to one, since one incoming P_REQ request may be outstanding at
one time. Two types of incoming requests are supported in UltraSPARC:
snoop and UPA_PORT_ID Register read.
UPACAP<4:0>:
This read-only field indicates the UPA capability of this module.
• UPACAP<4>:
Set, since UltraSPARC is an interrupt handler
(HandlerSlave). SC forwards P_INT_REQ to this port only if this bit is
set.
• UPACAP<3>:
Set, since UltraSPARC is an interrupter
(InterruptMaster). Software assigns this port the target-MID of an
interrupt handler if this bit is set.
• UPACAP<2>:
Clear, since UltraSPARC does not use the
UPA_Slave_Int_L signal.
• UPACAP<1>:
Set, since UltraSPARC has a cache (CacheMaster).
• UPACAP<0>:
Set, since UltraSPARC has a master interface (Master).
ID<15:0>
: A 16-bit field for module identification.
FC
16
63
56 55
35
34
33
32
31 30
25 24
21 20
16 15
0
—
ECC_Valid ONEREAD
PINT_RDQ PREQ_DQ
PREQ_RQ
UPACAP
ID
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