
8-50
G2 PowerPC Core Reference Manual
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MOTOROLA
Signal Descriptions
asserted during the assertion of core_hreset in order to properly
initialize the JTAG test access port. The core_trst signal must be
asserted to properly initialize the boundary scan chain. This may be
accomplished by connecting it to core_hreset, using logic to OR any
external JTAG core_trst drivers.
Negated—Indicates normal operation.
Assertion/Negation—This input contains an internal pull-up resistor
to ensure that an unterminated input appears as a high signal level
(negated) to the test logic.
Timing Comments
8.3.12.6 TLM TAP Enable (core_tap_en)—Input
The test linking module test access point enable (core_tap_en) signal is an input on the G2
core. Following are the state meaning and timing comments for the core_tap_en input
signal.
State Meaning
Asserted—Indicates that the test access point controller of the G2
core is in normal mode of operation which is controlled by core_tms.
Negated—Indicates that the core test access point enables the TLM
function.
Timing Comments
Assertion/Negation—This input signal should be either driven at low
logic state during normal operation or not connected to TLM logic.
8.3.12.7 Test Linking Module Select (core_tlmsel)—Output
The test linking module select (core_tlmsel) signal is an output on the G2 core. Following
are the state meaning and timing comments for core_tlmsel.
State Meaning
Asserted—Indicates that the core test access point controller selects
the TLM register by issuing a TLM instruction.
Negated—Indicates normal operation.
Timing Comments
Assertion/Negation—The test access point controller transitions to
run/test/ideal state until the core_tlmsel signal is re-enabled.
8.3.13 Test Interface
Test interface signals like LSSD test clock or test control signals are used in the G2 core for
production testing. core_l1_tstclk, core_l2_tsclk, and core_lssd_mode are the test clock
and test control signals.
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