3 jtag id codes, 4 test registers, 1 boundary scan register – Maxim Integrated DS33R11 User Manual

Page 341: 2 bypass register, 3 identification register, Boundary scan register, Bypass register, Identification register, Table 14-2. id code structure

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DS33R11 Ethernet Mapper with Integrated T1/E1/J1 Transceiver

341 of 344

14.3 JTAG ID Codes

Table 14-2. ID Code Structure

DEVICE

REVISION

ID[31:28]

DEVICE CODE

ID[27:12]

MANUFACTURER’S CODE

ID[11:1]

REQUIRED

ID[0]

Ethernet

Mapper

0000

0000 0000 0110 0001

000 1010 0001

1

T1/E1/J1

Transceiver

0000

0000 0000 0001 0000

000 1010 0001

1


14.4 Test Registers

IEEE 1149.1 requires a minimum of two test registers: the bypass register and the boundary scan register. An
optional test register has been included with the DS26521 design. This test register is the identification register
and is used in conjunction with the IDCODE instruction and the Test-Logic-Reset state of the TAP controller.

14.4.1 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 n bits in length.

14.4.2 Bypass Register

This is a single one-bit shift register used in conjunction with the BYPASS, CLAMP, and HIGHZ instructions, which
provides a short path between JTDI and JTDO.

14.4.3 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.

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