ST18-AU1 STMICROELECTRONICS [STMicroelectronics], ST18-AU1 Datasheet - Page 55

• Manufacturer Part Number: ST18-AU1
• Description: SIX-CHANNEL DOLBY AC3/MPEG2 AUDIO DECODER
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

14 JTAG IEEE 1149.1 TEST ACCESS PORT
The Test Access Port (TAP) conforms to IEEE standard 1149.1.
The TAP consists of five pins: TMS, TCK, TDI, TDO and TRST. TDO can be overdriven to the
power rails, and TCK can be stopped in either logic state.
The instruction register is 8 bits long, with no parity, and the pattern “00000001” is loaded into
the register during the Capture-IR state.
There are three defined public instructions, see Table 14.1. All other instruction codes are
reserved.
Table 14.1
1)
Instruction code
Instruction codes
MSB... LSB; LSB closest to TDO
FFh
04h
08h
1)
Instruction
BYPASS
IDCODE
EMU
Selected register
D950 IOscan
Identification
Bypass
ST18-AU1
55/87