Renesas SH7781 - Manual (Page 1520)

30. User Debugging Interface (H-UDI)
Rev.1.00 Jan. 10, 2008 Page 1490 of 1658
REJ09B0261-0100
Notes: 1. This pin is pulled up in the chip. In designing the board that can connect an emulator, or
using interrupts or resets through the H-UDI, there is no problem with putting the pull-up
resistor outside this LSI.
2. In designing the board that can connect an emulator, or using interrupts or resets
through the H-UDI, the
TRST pin should be set so that it can be held low while the
PRESET signal is low after power is turned on and the TRST pin can be controlled
independently.
3. This pin should be connected to ground, or connected to the same signal as the
PRESET, or a pin which operates in the same way as the PRESET pin. When this pin
is connected to ground, the following problem occurs. Since the
TRST pin is pulled up
within this LSI, weak current runs when the pin is connected to ground outside the LSI.
The current depends on a resistance of the pull-up for the port pin. Although this current
does not affect the operation of this LSI, it consumes unnecessary power.
The TCK clock or the CPG of this LSI should be set so that the frequency of the TCK clock is less
than that of the peripheral clock of this LSI. For details of the setting of the CPG, see section 15,
Clock Pulse Generator (CPG).