5 status register – Texas Instruments TSB12LV26 User Manual
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3–5
3.5
Status Register
The status register provides status over the TSB12LV26 interface to the PCI bus. All bit functions adhere to the
definitions in the
PCI Local Bus Specification. See Table 3–4 for a complete description of the register contents.
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Name
Status
Type
RCU
RCU
RCU
RCU
RCU
R
R
RCU
R
R
R
R
R
R
R
R
Default
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
Register:
Status
Type:
Read/Clear/Update, Read-only
Offset:
06h
Default:
0210h
Table 3–4. Status Register Description
BIT
FIELD NAME
TYPE
DESCRIPTION
15
PAR_ERR
RCU
Detected parity error. This bit is set when a parity error is detected, either address or data parity errors.
14
SYS_ERR
RCU
Signaled system error. This bit is set when PCI_SERR is enabled and the TSB12LV26 has signaled a
system error to the host.
13
MABORT
RCU
Received master abort. This bit is set when a cycle initiated by the TSB12LV26 on the PCI bus has been
terminated by a master abort.
12
TABORT_REC
RCU
Received target abort. This bit is set when a cycle initiated by the TSB12LV26 on the PCI bus was
terminated by a target abort.
11
TABORT_SIG
RCU
Signaled target abort. This bit is set by the TSB12LV26 when it terminates a transaction on the PCI bus
with a target abort.
10–9
PCI_SPEED
R
DEVSEL timing. Bits 10–9 encode the timing of PCI_DEVSEL and are hardwired to 01b indicating that
the TSB12LV26 asserts this signal at a medium speed on nonconfiguration cycle accesses.
8
DATAPAR
RCU
Data parity error detected. This bit is set when the following conditions have been met:
a. PCI_PERR was asserted by any PCI device including the TSB12LV26.
b. The TSB12LV26 was the bus master during the data parity error.
c. The parity error response bit is set in the PCI command register (offset 04h, see Section 3.4).
7
FBB_CAP
R
Fast back-to-back capable. The TSB12LV26 cannot accept fast back-to-back transactions; thus, this
bit is hardwired to 0.
6
UDF
R
User definable features (UDF) supported. The TSB12LV26 does not support the UDF; thus, this bit is
hardwired to 0.
5
66MHZ
R
66-MHz capable. The TSB12LV26 operates at a maximum PCI_CLK frequency of 33 MHz; therefore,
this bit is hardwired to 0.
4
CAPLIST
R
Capabilities list. This bit returns 1 when read, indicating that capabilities additional to standard PCI are
implemented. The linked list of PCI power management capabilities is implemented in this function.
3–0
RSVD
R
Reserved. Bits 3–0 return 0s when read.