Figure 1035.Conceptual Block Diagram Of The Apu Functions - STMicroelectronics SPC572L series Reference Manual

IEEE 1149.7 Compact JTAG Test Access Port Controller (CJTAG)
The Scan Control, Configuration Control, and Transport Control functions are idled when
the Standard Protocol is used as the Bypass Function connects the TCKC and TMSC pins
to the EPU.
TAP
Interface
Wide or
Narrow
TAP.7
The APU's internal interface includes a connection to EPU registers, the EPU's TAP
interface, connections to chip-level data channels (when they are implemented), and reset
signaling with the EPU. The APU's TAP interface provides mutually exclusive use of the
TMSC pin for:
• Bypass Function
•
Scan Control Function
• Configuration Control Function
When the Standard Protocol is used, the APU's Bypass function connects the EPU directly
to the TAP.7 pins. When the TDIC and TDOC pin functions are not available (narrow TAP.7
or TDIC and TDOC pin functions are an alternate function), the APU sources a logic 1 to the
EPU inputs associated with these pins.
When the Advanced Protocol is used, the APU multiplexes the use of the TMSC pin
between the other APU functions. Scan Control acts as a serial to parallel converter,
translating the parallel information at the EPU's TAP interface into bidirectional serial
transfers. Since the Scan Control is literally a protocol adaptor, the entire EPU infrastructure
1780/2058
Figure 1035. Conceptual block diagram of the APU functions
T4 Registers, Commands, and Logic
Bypass Function (Std. Protocol)
Scan Control Function (Adv. Protocol)
Configuration Control Function
DocID027809 Rev 4
EPU
APU
(Adv. Protocol)
RSU
Ancillary Services
RM0400
Internal
Interface
EPU
TAP
Reset