29 September 1997 – Subject To Change
Internal Processor Registers
5–63
External Interface Control (CBU) IPRs
5.3.3 CBU Status (CBOX_STATUS) Register (FF FFF0 0108)
CBOX_STATUS is a read-only register. It is locked when any of the error bits are
set. Additional errors set the MULTI_ERR error bit in CBOX_STATUS. A read of
CBOX_STATUS unlocks and clears CBOX_STATUS and unlocks CBOX_ADDR.
Figure 5–50 and Table 5–28 describe the CBOX_STATUS register format.
Figure 5–50 CBU Status (CBOX_STATUS) Register
Table 5–28 CBU Status Register Fields
(Sheet 1 of 2)
Name
Extent
Type
Description
Reserved
<03:00> RO,0 Reserved to DIGITAL. Must be zero (MBZ).
SYS_CLK_
RATIO<3:0>
<07:04> RO,0 The sysclk period in CPU cycles. The sysclk ratio is
loaded from the IRQ pins on reset. Note that this field
is read only.
CHIP_REV<3:0> <11:08> RO,0 This field displays 0001, the current revision of the
chip. Future update revisions of the chip will return
different unique values.
DATA_PAR_
ERR<3:0>
<15:12> RO,0 If set, this field indicates that the corresponding long-
word had a parity error. Bit<0> corresponds to
data_h<31:0>, bit<3> corresponds to
data_h<127:96>.
TAG_PAR_ERR
<16>
RO,0 If set, a parity error was detected on the Bcache tag
store.
PCA006
31
00
63
32
07
12 11
16 15
18
19
20
23
24
25
26
27
28
30
MBZ
08
MBZ
04 03
22
14 13
CHIP_REV<3:0>
TAG_PAR_ERR
TAG_DIRTY
MEMORY
MULTI_ERR
DATA_PAR_ERR<3:0>
SYS_CLK_RATIO<3:0>
MBZ
17