DS3112
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11.3.3
11.2.6 CLAMP
All digital outputs will output data from the boundary scan parallel output while connecting the Bypass
Register between JTDI and JTDO. The outputs will not change during the CLAMP instruction.
11.3 Test Registers
IEEE 1149.1 requires a minimum of two test registers, the bypass register and the boundary scan register.
An optional test register, the Identification register, has been included in the DS3112 design. It is used in
conjunction with the IDCODE instruction and the Test-Logic-Reset state of the TAP controller.
11.3.1 Bypass Register
This is a single one-bit shift register used in conjunction with the BYPASS, CLAMP, and HIGH-Z
instructions that provides a short path between JTDI and JTDO.
11.3.2 Identification Register
The Identification register contains a 32-bit shift register and a 32-bit latched parallel output. This register
is selected during the IDCODE instruction and when the TAP controller is in the Test-Logic-Reset state.
Boundary Scan Register
This register contains both a shift register path and a latched parallel output for all control cells and
digital I/O cells and is 196 bits in length.
shows all the cell bit locations and definitions.
Table 11-2. Boundary Scan Control Bits
BIT SYMBOL
PIN
I/O OR CONTROL BIT
DESCRIPTION
0 OUT_ENB
Control
bit
0 = outputs are active
1 = outputs are tri-state (“z”)
1 TEST
C3
I
2 CINT_ENB_N
Control
bit
0 =
CINT
is a zero (“0”)
1 =
CINT
is tri-state (“z”)
3
CINT_OUT
A2
O (open drain)
4 CINT_IN
A2 I
5 CMS
B2
I
6 CIM
B3
I
7
CCS
C4 I
8
CRD
D5 I
9
CWR
A3 I
10 T3E3MS
B4 I
11
RST
C5 I
12 G.747E
B6 I
13 CALE
C7
I
14 FRMECU
A7 I
15 FRLOF
C8 O
16 FRLOS
B8 O
17 FRSOF
A8 O
18 FRDEN
C9 O
19 FRD
B9
O
20 FRCLK
A9 O
21 FTDEN
C10
O