MOTOROLA
Chapter 31. IEEE 1149.1 Test Access Port (JTAG)
31-3
Modes of Operation
31.2 Modes of Operation
The JTAG_EN pin can select between the following modes of operation:
• JTAG mode
• BDM - background debug mode (For more information, refer to Section 29.5,
“Background Debug Mode (BDM)).”
31.3 External Signal Description
The JTAG module has five input and one output external signals, as described in
Table 31-1.
31.3.1 Detailed Signal Description
31.3.1.1 JTAG_EN — JTAG Enable
The JTAG_EN pin selects between Debug module and JTAG. If JTAG_EN is low, the
Debug module is selected; if it is high, the JTAG is selected. Table 31-2 summarizes the pin
function selected depending upon JTAG_EN logic state.
When one module is selected, the inputs into the other module are disabled or forced to a
known logic level as shown in Table 31-3, in order to disable the corresponding module.
Table 31-1. Signal Properties
Name
Direction
Function
Reset State
Pull up
JTAG_EN
Input
JTAG/BDM selector input
—
—
TCLK
Input
JTAG Test clock input
—
Active
TMS/BKPT
Input
JTAG Test mode select / BDM Breakpoint
—
Active
TDI/DSI
Input
JTAG Test data input / BDM Development serial input
—
Active
TRST/DSCLK
Input
JTAG Test reset input / BDM Development serial clock
—
Active
TDO/DSO
Output
JTAG Test data output / BDM Development serial output
Hi-Z / 0
—
Table 31-2. Pin Function Selected
JTAG_EN = 0
JTAG_EN = 1
Pin Name
Module selected
BDM
JTAG
—
Pin Function
—
BKPT
DSI
DSO
DSCLK
TCLK
TMS
TDI
TDO
TRST
TCLK
BKPT
DSI
DSO
DSCLK
Summary of Contents for ColdFire MCF5281
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Page 168: ...6 26 MCF5282 User s Manual MOTOROLA Interrupts ...
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Page 228: ...9 22 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 246: ...10 18 MCF5282 User s Manual MOTOROLA Low Power Wakeup Operation ...
Page 254: ...11 8 MCF5282 User s Manual MOTOROLA Memory Map and Registers ...
Page 264: ...12 10 MCF5282 User s Manual MOTOROLA Chip Select Registers ...
Page 280: ...13 16 MCF5282 User s Manual MOTOROLA Misaligned Operands ...
Page 314: ...14 34 MCF5282 User s Manual MOTOROLA MCF5282 External Signals ...
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Page 340: ...15 26 MCF5282 User s Manual MOTOROLA SDRAM Example ...
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Page 408: ...17 52 MCF5282 User s Manual MOTOROLA Buffer Descriptors ...
Page 446: ...20 24 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 474: ...22 18 MCF5282 User s Manual MOTOROLA Programming Model ...
Page 510: ...23 36 MCF5282 User s Manual MOTOROLA Operation ...
Page 526: ...24 16 MCF5282 User s Manual MOTOROLA I2C Programming Examples ...
Page 672: ...28 12 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 718: ...29 46 MCF5282 User s Manual MOTOROLA Motorola Recommended BDM Pinout ...
Page 750: ...32 8 MCF5282 User s Manual MOTOROLA Ordering Information ...