IDT JTAG & Boundary Scan
Revision 1.5
Integrated Device Technology, Inc.
CPS-16/12/8 User Manual
6 - 3
July 10, 2012
6.5.1 Configuration Register Access -- Writes
When bit 0 of the data stream is 0, data shifted in after the address is written to the address specified in
jtag_config_addr. The TDO pin will transmit all 0s. Timing is shown below.
Figure 6.1 JTAG Write Access
The device is capable of reporting an unexpected termination of a register writes via JTAG and that JTAG
sourced write data is not on a 32-bit boundary. This will apply to writes to Configuration Registers. The
error code for this report is defined in the Error Management chapter of this document.
6.5.2 Configuration Register Access -- Reads
When bit 0 of the data stream is 1, data shifted out is read from the address specified in jtag_config_addr.
TDI is not used after the address is shifted in. Timing is shown below.
Figure 6.2 JTAG Read Access
6.6 BOUNDARY SCAN
JTAG instructions are provided for the purpose of making all the part inputs observable and all the outputs
controllable.
All external I/Os are designed to support Boundary Scan testing as defined in IEEE 1149.1 and 1149.6
converting digital and AC-coupled I/Os respectively. All input / output possibilities are tested including
support for leakage testing, and providing users easy debugging by isolating the CPS from other devices on
a PCB board.
Shift_dr
Capture_dr
Shift_dr
Pause_dr
Exit1_dr
Exit2_dr
Update_dr
Exit1_dr
Exit2_dr
Pause_dr
Select_dr_scan
TAP controller
state
TDO
Z
Z
Z
Internal
address
Address
Internal
data
Data
Address
Data
TDI
Shift_dr
Capture_dr
Shift_dr
Pause_dr
Exit1_dr
Exit2_dr
Update_dr
Exit1_dr
Exit2_dr
Pause_dr
Select_dr_scan
TAP controller
state
TDI
Address
TDO
Z
Z
Z
Data
Read latency
Data 1
Internal
address
Address
Internal
data
Data