8–12
Chapter 8: JTAG Boundary-Scan Testing in MAX V Devices
IEEE Std. 1149.1 BST Operation Control
Figure 8–11 resembles the SAMPLE/PRELOADwaveform diagram, except that the
instruction code for EXTESTis different. The data shifted out of TDOconsists of the data
that was present in the capture registers after the capture phase. New test data shifted
into the TDIpin appears at the TDOpin after being clocked through the entire
boundary-scan register.
Figure 8–11. EXTEST Shift Data Register Waveforms
TCK
TMS
TDI
TDO
SHIFT_IR
SHIFT_DR
TAP_STATE
EXIT1_IR
UPDATE_IR
EXIT1_DR
SELECT_DR_SCAN
After boundry-scan
register data has been
shifted out, data
entered into TDI will
shift out of TDO.
Data stored in
boundary-scan
register is shifted
out of TDO.
Instruction Code
UPDATE_DR
CAPTURE_DR
BYPASS Instruction Mode
You can activate BYPASSinstruction mode with an instruction code made up of only
ones. Figure 8–12 shows how scan data passes through a device after the TAP
controller is in the SHIFT_DRstate. In this state, data signals are clocked into the bypass
register from TDIon the rising edge of TCKand out of TDOon the falling edge of the
same clock pulse.
Figure 8–12. BYPASS Shift Data Register Waveforms
TCK
TMS
Bit 1
Bit 2
Bit 1
Bit 3
Bit 2
TDI
Bit n
TDO
SHIFT_IR
TAP_STATE
SHIFT_DR
SELECT_DR_SCAN
EXIT1_DR
UPDATE_DR
EXIT1_IR
Data shifted into TDI on
the rising edge of TCK is
shifted out of TDO on the
falling edge of the same
TCK pulse.
UPDATE_IR
CAPTURE_DR
Instruction Code
IDCODE Instruction Mode
Use IDCODEinstruction mode to identify the devices in an IEEE Std. 1149.1 chain.
When you select IDCODE, the device identification register loads with the 32-bit
vendor-defined identification code. The device ID register is connected between the
TDIand TDOports and the device IDCODEis shifted out.
f
IDCODEinstruction mode for MAX V devices are listed in the JTAG and In-System
Programmability in MAX V Devices chapter.
MAX V Device Handbook
December 2010 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
