MAC7200 datasheet(226/976 Pages) FREESCALE

226 / 976 page

A7S Nexus3 Programmers Model

MAC7200 Microcontroller Family Reference Manual, Rev. 2

148

Freescale Semiconductor

Table 11-18 and Table 11-19 illustrate examples of Direct Branch Messages: one with 2 MDO / 1 MSEO,

and one with 8 MDO / 2 MSEO.

Note that T0 and I0 are the least significant bits where:

•

Tx = TCODE number (fixed)

•

Sx = Source processor (fixed)

•

Ix = Number of Instructions (variable)

11.10 A7S Nexus3 Programmers Model

This section describes the A7S Nexus3 programmers model. Nexus registers are accessed using the JTAG

port in compliance with IEEE 1149.1 (discussed in Section 11.10.4, “Nexus Register Access via JTAG”).

11.10.1 JTAG ID Register

This JTAG ID Register (located within the ARM7 CPU) provides key development attributes to the

development tool concerning the ARM7 processor and the A7S Nexus3 block. This register is fixed for

each ARM7 embedded system.

This register is accessed through the standard JTAG IR/DR paths.

Table 11-18. Direct Branch Message Example (2 MDO / 1 MSEO)

Clock

MDO[1:0]

MSEO

State

Idle (or end of last message)

Start Message

Normal Transfer

End Packet

End Message

Start Message

Table 11-19. Direct Branch Message Example (8 MDO / 2 MSEO)

Clock

MDO[7:0]

MSEO[1:0]

State

Idle (or end of last message)

Start Message

End Packet/End Message

Start Message

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