SH7058 Datasheet, PDF (765/1130 Pages) Renesas Technology Corp – Renesas SuperHTM RISC engine

19.4.3 H-UDI Reset
The H-UDI can be reset in the following cases.
• When the TRST signal is held at 0.
• When TRST = 1 and at least five TCK clock cycles are input while TMS = 1.
• When the MSTOP2 bit in SYSCR2 is set to 1 (see section 25.2.3).
• In hardware standby mode.
19.5 Boundary Scan
The H-UDI pins can be placed in the boundary scan mode stipulated by IEEE1149.1 by setting a
command in SDIR.
19.5.1 Supported Instructions
The SH7058 supports the three essential instructions defined in IEEE1149.1 (BYPASS,
SAMPLE/PRELOAD, and EXTEST) and optional instructions (CLAMP, HIGHZ, and IDCODE).
BYPASS: The BYPASS instruction is an essential standard instruction that operates the bypass
register. This instruction shortens the shift path to speed up serial data transfer involving other
chips on the printed circuit board. While this instruction is executing, the test circuit has no effect
on the system circuits. The instruction code is 1111.
SAMPLE/PRELOAD: The SAMPLE/PRELOAD instruction inputs values from the SH7058’s
internal circuitry to the boundary scan register, outputs values from the scan path, and loads data
onto the scan path. When this instruction is executing, the SH7058’s input pin signals are
transmitted directly to the internal circuitry, and internal circuit values are directly output
externally from the output pins. The SH7058’s system circuits are not affected by execution of
this instruction. The instruction code is 0100.
In a SAMPLE operation, a snapshot of a value to be transferred from an input pin to the internal
circuitry, or a value to be transferred from the internal circuitry to an output pin, is latched into the
boundary scan register and read from the scan path. Snapshot latching does not affect normal
operation of the SH7058.
In a PRELOAD operation, an initial value is set in the parallel output latch of the boundary scan
register from the scan path prior to the EXTEST instruction. Without a PRELOAD operation,
when the EXTEST instruction was executed an undefined value would be output from the output
pin until completion of the initial scan sequence (transfer to the output latch) (with the EXTEST
instruction, the parallel output latch value is constantly output to the output pin).
EXTEST: This instruction is provided to test external circuitry when the SH7058 is mounted on a
printed circuit board. When this instruction is executed, output pins are used to output test data
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