Escape Sequences - STMicroelectronics SPC572L series Reference Manual

IEEE 1149.7 Compact JTAG Test Access Port Controller (CJTAG)
60.7.2.2 CPA
The CPA state allocates the use of the TMSC pin to a CP. This state is entered in one of
three ways:
•
As a result of a TAP.7 controller reset when the TAP.7 controller starts up offline.
•
A value specifying the use of the Advanced Protocol is written to the SCNFMT Register
when using the Standard Protocol.
•
A TAP.7 controller register write occurs when using the Advanced Protocol.
60.7.2.3 SPA
The SPA state allocates the use of the TMSC pin to an SP. This state is entered when the
SCNFMT Register specifies the use of the Advance Protocol when a CP ends.
60.7.3

Escape sequences

Escape-sequence detection provides services to the Reset Logic, Scan, Configuration
Control, and Transport Control functions as outlined below:
•
Scan and Transport Control – End of Transfer (EOT) escape sequence detected.
•
Configuration Control – Synchronize Advanced Protocol (SAP) escape sequence.
•
Reset Logic – Reset (RES) escape sequence detected.
An EOT escape sequence is used to increase the efficiency of OScan Scan formats.
An SAP escape sequence is used to place TAP.7 controllers online.
A RES escape sequence asynchronously causes generation of a Type-3 Reset. Following
a RES escape sequence, the drive of the TMSC pin is inhibited so it is not driven when
TCKC becomes a logic 0 immediately following the RES escape sequence.
60.7.4 Signal behaviors
The TCKC signal:
•
The test clock
The TMSC signal:
•
An input when the Standard Protocol is used
•
Bi-directional when the Advanced Protocol is used
The TDI and TDO signals:
•
Deleted with a narrow TAP.7
•
One of two functions with a wide TAP.7
–
–
60.7.5 APU Functions
60.7.5.1 Bypass Active (BPA) Function
When the Standard Protocol is used, the APU connects the EPU inputs and outputs directly
to the TAP.7 pins. If the TDIC and TDOC pin functions are not present (e.g., a narrow TAP.7
1782/2058
Fixed – as the TAP.7 TDIC and TDOC pin functions, or
Programmable – as the TAP.7 TDIC and TDOC signal functions or alternate
functions with a TAP.7 controller reset establishing the default signal function.
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