Thales Computers 2-4 CPMC-1553R User’s Guide, CA.DT.356-0e
2.2.1.4 Status Register The Status Register is a 16-bit read/write register that provides the status of bus-
related events. Read transactions tell you the current status of the bits. The Status Register is cleared by
writing a logic one to that bit. Writing a logic zero has no affect on the registers. The status register is
defined in Table 5. The default value of the status register is 0x0400.
Table 5. Status Register Definition
Data Bit Mnemonic Read/Write Definition
8..0 Unused ——
10..9 DEVSEL_TIM Read Device Select Timing. The DEVSEL_TIM bits
indicate target access timing of the CPMC-1553R
board function. This board function is designed to be
a slow target device. These bits are always read as
0x10b.
11 TABORT_SIG Read/Write Target Abort Signaled. This bit is set when a local
peripheral device terminates a transaction. The
CPMC-1553R board automatically sets this bit if it
issued a target abort after the local side asserted
LT_ABORT*. This bit is driven to the local side on
the TABORT_SIG output.
12 TAR_ABRT_REC Read/Write Target Abort. When high, TAR_ABRT_REC
indicates that the current target device transaction has
been terminated.
13 Unused ——
14 SERR_SET Read/Write Signaled System Error. When high, SERR_SET
indicates that the CPMC-1553R board drove the
SERR* output active (result of address phase parity
error). This signal is driven to the local side on the
SERR_SIG output
15 DET_PAR_ERR Read/Write Detected Parity Error. When high, DET_PAR_ERR
indicates that the CPMC-1553R board detected either
an address or data parity error. Even if parity error
reporting is disabled (PERR_ENA), the CPMC-1553R
board sets the DET_PAR_ERR bit. This signal is
driven to the local side on the PERR_DET output.
2.2.1.5 Revision ID Register The Revision ID register is an 8-bit, read-only register that identifies the
revision number of the device. The value of this register is set by Thales Computers. The current version
should be 0x03 or higher.
2.2.1.6 Class Code Register The Class Code register is a 24-bit, read-only register divided into three
sub-registers: base class, sub-class, and programming interface. The class code register always returns a
value of 0x078000 when read.
2.2.1.7 Cache Line Size Register The Cache Line Size register is not supported.