Rainbow Electronics DS3170 - Manual (Page 206)

DS3170 DS3/E3 Single-Chip Transceiver
206 of 233
CLAMP. All digital output pins output data from the boundary scan parallel output while connecting the bypass
register between JTDI and JTDO. The outputs do not change during the CLAMP instruction. If the previous
instruction was not EXTEST, the outputs will be driven according to the values in the boundary scan register at the
positive edge of JTCLK in the Update-IR state. The typical use of this instruction is in a system that has the JTAG
scan chain of multiple chips connected in series, and all of the chips have their outputs initialized using the
EXTEST mode. Then some of the chips are left initialized using the CLAMP mode and others have their IO
controlled using the EXTEST mode. This reduces the size of the scan chain during the partial testing of the system.
12.4 JTAG ID Codes
Table 12-2. JTAG ID Codes
DEVICE
REVISION
ID[31:28]
DEVICE CODE
ID[27:12]
MANUFACTURER’S CODE
ID[11:1]
REQUIRED
ID[0]
DS3170 Consult factory 0000000001001111 00010100001 1