dsp56854 Freescale Semiconductor, Inc, dsp56854 Datasheet - Page 22

• Manufacturer Part Number: dsp56854
• Description: 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

22
Pin No.
Table 3-1. 56854 Signal and Package Information for the 128-pin LQFP (Continued)
50
49
Signal Name
TRST
DE
Input/Output
Type
Input
56854 Technical Data, Rev. 6
Test Reset (TRST)—As an input, a low signal on this pin provides a
reset signal to the JTAG TAP controller. To ensure complete
hardware reset, TRST should be asserted whenever RESET is
asserted. The only exception occurs in a debugging environment,
since the Enhanced OnCE/JTAG module is under the control of the
debugger. In this case it is not necessary to assert TRST when
asserting RESET . Outside of a debugging environment RESET
should be permanently asserted by grounding the signal, thus
disabling the Enhanced OnCE/JTAG module on the device.
Note:
design is to be used in a debugging environment, TRST may be tied to V
through a 1K resistor.
Debug Event (DE)—This is an open-drain, bidirectional, active low
signal. As an input, it is a means of entering debug mode of
operation from an external command controller. As an output, it is a
means of acknowledging that the chip has entered debug mode.
This pin is connected internally to a weak pull-up resistor.
For normal operation, connect TRST directly to V
Description
Freescale Semiconductor
SS
. If the
SS