dsp56857 Freescale Semiconductor, Inc, dsp56857 Datasheet - Page 20

• Manufacturer Part Number: dsp56857
• Description: Dsp56857 Digital Signal Controller
• Manufacturer: Freescale Semiconductor, Inc

20
Pin No.
Table 3-1 56857 Signal and Package Information for the 100-pin LQFP (Continued)
40
39
Signal Name
TRST
DE
Input/Output
Type
Input
56857 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:
be used in a debugging environment, TRST may be tied to V
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
SS
. If the design is to
through a 1K