Datasheet

DS21352/DS21552
23 of 137
4.1.4 JTAG TEST ACCESS PORT PINS
Signal Name:
JTRST
Signal Description:
IEEE 1149.1 Test Reset
Signal Type:
Input
If FMS = 1: JTAG functionality is not available and JTRST is held LOW internally.
If FMS = 0: JTAG functionality is available and JTRST is pulled up internally by a 10kΩ resistor.
If FMS = 0 and boundary scan is not used, this pin should be held low. This signal is used to asynchronously reset the test
access port controller. The device operates as a T1/E1 transceiver if JTRST is pulled low.
Signal Name:
JTMS
Signal Description:
IEEE 1149.1 Test Mode Select
Signal Type:
Input
This pin is sampled on the rising edge of JTCLK and is used to place the test access port into the various defined IEEE 1149.1
states. This pin has a 10k pull up resistor.
Signal Name:
JTCLK
Signal Description:
IEEE 1149.1 Test Clock Signal
Signal Type:
Input
This signal is used to shift data into JTDI on the rising edge and out of JTDO on the falling edge.
Signal Name:
JTDI
Signal Description:
IEEE 1149.1 Test Data Input
Signal Type:
Input
Test instructions and data are clocked into this pin on the rising edge of JTCLK. This pin has a 10k pull up resistor.
Signal Name:
JTDO
Signal Description:
IEEE 1149.1 Test Data Output
Signal Type:
Output
Test instructions and data are clocked out of this pin on the falling edge of JTCLK. If not used, this pin should be left
unconnected.
4.1.5 INTERLEAVE BUS OPERATION PINS
Signal Name:
CI
Signal Description:
Carry In
Signal Type:
Input
A rising edge on this pin causes RSER and RSIG to come out of high Z state and TSER and TSIG to start sampling on the next
rising edge of RSYSCLK/TSYSCLK beginning an I/O sequence of 8 or 256 bits of data. This pin has a 10k pull up resistor.
Signal Name:
CO
Signal Description:
Carry Out
Signal Type:
Output
An output that is set high when the last bit of the 8 or 256 IBO output sequence has occurred on RSER
and RSIG.