Motorola MCF5281 사용자 설명서
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,
• BDM - background debug mode (For more information, refer to Section 29.5,
31.3 External Signal Description
The JTAG module has five input and one output external signals, as described in
Table 31-1.
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.
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.
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
BKPT
DSI
DSO
DSCLK