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PI7C8150A
2-PORT PCI-TO-PCI BRIDGE
Page 99 of 111
APRIL 2006 – Revision 1.1
15.2.3
REPORTING PARITY ERRORS
For all address phases, if a parity error is detected, the error should be reported on the
P_SERR_L signal by asserting P_SERR_L for one cycle and then 3-stating two cycles
after the bad address. P_SERR_L can only be asserted if bit 6 and 8 in the Command
Register are both set to 1. For write data phases, a parity error should be reported by
asserting the P_PERR_L signal two cycles after the data phase and should remain asserted
for one cycle when bit 6 in the Command register is set to a 1. The target reports any type
of data parity errors during write cycles, while the master reports data parity errors during
read cycles.
Detection of an address parity error will cause the PCI-to-PCI Bridge target to not claim
the bus (P_DEVSEL_L remains inactive) and the cycle will then terminate with a Master
Abort. When the bridge is acting as master, a data parity error during a read cycle results in
the bridge master initiating a Master Abort.
15.2.4
SECONDARY IDSEL MAPPING
When PI7C8150A detects a Type 1 configuration transaction for a device connected to
the secondary, it translates the Type 1 transaction to Type 0 transaction on the downstream
interface. Type 1 configuration format uses a 5-bit field at P_AD[15:11] as a device
number. This is translated to S_AD[31:16] by PI7C8150A.
16
IEEE 1149.1 COMPATIBLE JTAG CONTROLLER
An IEEE 1149.1 compatible Test Access Port (TAP) controller and associated TAP pins
are provided to support boundary scan in PI7C8150A for board-level continuity test and
diagnostics. The TAP pins assigned are TCK, TDI, TDO, TMS and TRST_L. All digital
input, output, input/output pins are tested except TAP pins.
The IEEE 1149.1 Test Logic consists of a TAP controller, an instruction register, and
a group of test data registers including Bypass and Boundary Scan registers. The TAP
controller is a synchronous 16-state machine driven by the Test Clock (TCK) and the Test
Mode Select (TMS) pins. An independent power on reset circuit is provided to ensure the
machine is in TEST_LOGIC_RESET state at power-up. The JTAG signal lines are not
active when the PCI resource is operating PCI bus cycles.
PI7C8150A implements 3 basic instructions: BYPASS, SAMPLE/PRELOAD, and
EXTEST.
16.1
BOUNDARY SCAN ARCHITECTURE
Boundary-scan test logic consists of a boundary-scan register and support logic. These are
accessed through a Test Access Port (TAP). The TAP provides a simple serial interface
that allows all processor signal pins to be driven and/or sampled, thereby providing direct
control and monitoring of processor pins at the system level.
06-0057