tm1300 NXP Semiconductors, tm1300 Datasheet - Page 256

• Manufacturer Part Number: tm1300
• Description: Tm-1300 Media Processor
• Manufacturer: NXP Semiconductors

TM1300 Data Book
Note: when a register is scanned, its old value is shifted
out of TDO. The new value shifted in via TDI is written to
the register at the update state. Hence, scan in/out in-
volve the same steps. This also means that reading a
register via JTAG destroys its contents unless otherwise
stated. We can specify some registers as read-only via
JTAG so that when the controller transitions to update
state for the read-only register, the update has no effect.
Sometimes, read-write registers are needed (for exam-
ple, control registers used for handshake) which can be
read non-destructively. In such cases, the value shifted
in determines whether the old value is ‘remembered’ or
something else happens.
18.2.2
TM1300 uses a 5-bit instruction register. The unspecified
opcodes are private and their effects are undefined.
Table 18-1
18-2
Figure 18-1. State diagram of TAP controller
TM1300 JTAG Instruction Set
lists the JTAG instructions.
0
1
Test Logic
Reset
Run-Test/
Idle
0
PRODUCT SPECIFICATION
1
1
0
Select
DR Scan
Capture
DR
Shift
Exit1
DR
Pause
DR
Exit2
DR
Update
DR
DR
1
0
0
1
1
1
0
0
Table 18-1. JTAG instruction encoding
Encoding
1
00000
00001
11111
10000
10001
10010
10011
10100
10101
1
0
0
EXTEST
SAMPLE/PRELOAD Select (dummy) boundary
BYPASS
RESET
SEL_DATA_IN
SEL_DATA_OUT
SEL_IFULL_IN
SEL_OFULL_OUT
SEL_JTAG_CTRL
Instruction name
1
0
Select
IR Scan
Capture
IR
Shift
IR
Exit1
IR
Pause
IR
Exit2
IR
Update
IR
1
Philips Semiconductors
Select (dummy) boundary
scan register
scan register
Select bypass register
Reset TriMedia to power on
state
Select DATA_IN register
Select DATA_OUT register
Select IFULL_IN register
Select OFULL_OUT regis-
ter
Select JTAG_CTRL regis-
ter
0
0
1
1
1
0
0
1
1
Action
0
0