Renesas SH7781 - Manual (Page 1517)

30. User Debugging Interface (H-UDI)
Rev.1.00 Jan. 10, 2008 Page 1487 of 1658
REJ09B0261-0100
Section 30 User Debugging Interface (H-UDI)
The H-UDI is a serial input/output interface which supports to a subset of JTAG (IEEE 1149.1).
The H-UDI is used to connect emulators.
30.1 Features
The H-UDI is a serial input/output interface which supports to a subset of JTAG (IEEE 1149.1:
IEEE Standard Test Access Port and Boundary-Scan Architecture). The H-UDI is used to connect
emulators. Do not use the JTAG functions of this interface when using an emulator. For the
method of connecting the emulator, see emulator manuals.
The H-UDI has six pins, the TCK, TMS, TDI, TDO,
TRST, and ASEBRK/BRKACK pins. The
pin functions except
ASEBRK/BRKACK, and serial transfer protocols conform to JTAG with the
subset. Also, the H-UDI has six signals (AUDSYNC, AUDCK, and AUDATA3 to AUDATA0)
used for emulator pins, and a signal (MPMD) for the chip mode select pin.
In the H-UDI in this LSI, the boundary-scan test access port (TAP) controller is separated from the
TAP controller for other H-UDI function control. When the
TRST is asserted (including when the
power is turned on), the boundary-scan TAP controller is selected. Therefore, the switching
command should be input to use the H-UDI functions. The boundary-scan TAP controller cannot
be accessed through the CPU.
Figure 30.1 shows a block diagram of the H-UDI.
The H-UDI circuit has TAP controllers and four registers (SDBPR, SDBSR, SDIR, and SDINT).
SDBPR supports the JTAG bypass mode, SDBSR supports the JTAG boundary scan mode, SDIR
is used for commands, and SDINT is used for H-UDI interrupts. SDIR can be directly accessed
through the TDI and TDO pins.
Without reset pins of the chip, the TAP controller, control registers, and boundary-scan TAP
controller are reset when the
TRST pin is set to low or when five or more TCK cycles are elapsed
after TMS is set to 1. The other circuits are reset in a normal reset period, and initialized.