Pin Configuration; Table 21.1 H-Udi Pins - Hitachi SH7750 Hardware Manual

21.1.3

Pin Configuration

Table 21.1 shows the H-UDI pin configuration.

Table 21.1 H-UDI Pins

Pin Name Abbreviation
Clock pin TCK
Mode pin TMS
TRST
Reset pin
Data input TDI
pin
Data output TDO
pin
Emulator pin ASEBRK/
BRKACK
Notes: *1 Pulled up inside the chip. When designing a board that allows use of an emulator, or
when using interrupts and resets via the H-UDI, there is no problem in connecting a
pullup resistance externally.
*2 When designing a board that enables the use of an emulator, or when using interrupts
and resets via the H-UDI, drive TRST low for a period overlapping RESET at power-on,
and also provide for control by TRST alone.
*3 Fixed to the ground or connected to the same signal line as RESET, or to a signal line
that behaves in the same way. However, there is a problem when this pin is fixed to the
ground. TRST is pulled up in the chip so, when this pin is fixed to the ground via
external connection, a minute current will flow. The size of this current is determined by
I/O Function
Input Same as the JTAG serial clock input
pin. Data is transferred from data
input pin TDI to the H-UDI circuit, and
data is read from data output pin
TDO, in synchronization with this
signal.
Input The mode select input pin. Changing
this signal in synchronization with
TCK determines the meaning of the
data input from TDI. The protocol
conforms to the JTAG (IEEE Std
1149.1) specification.
Input The input pin that resets the H-UDI.
This signal is received
asynchronously with respect to TCK,
and effects a reset of the JTAG
interface circuit when low. TRST must
be driven low for a certain period
when powering on, regardless of
whether or not JTAG is used. This
differs from the IEEE specification.
Input The data input pin. Data is sent to the
H-UDI circuit by changing this signal
in synchronization with TCK.
Output The data output pin. Data is sent to
the H-UDI circuit by reading this
signal in synchronization with TCK.
Input/ Dedicated emulator pin
output
When Not Used
1
Open *
1
Open *
2 3
* *
1
Open *
Open
1
Open *
Rev. 6.0, 07/02, page 801 of 986