MAC7200 datasheet(173/976 Pages) FREESCALE

Part #	MAC7200

Description	MAC7200 Microcontroller Family Reference Manual

PDF	976 Pages

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Manufacturer	FREESCALE [Freescale Semiconductor, Inc]

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Debug Implementation

MAC7200 Microcontroller Family Reference Manual, Rev. 2

Freescale Semiconductor

8.4.2

Synchronization

As with any external input, it is necessary to synchronize the TCK, TMS and TDI inputs to the internal

clock of the TAP state machine (ipg_clk). However, in the case of these signals, it is not necessary to

synchronize all three signals, as TMS and TDI are driven externally with respect to TCK. Therefore, the

synchronization can be performed by synchronizing the TCK input, and then generating an enable

(tap_enable) signal from this synchronization logic that is used to strobe the TMS and TDI inputs. The

actual logic is illustrated in Figure 8-6, and the timing is described in Figure 8-7.

Figure 8-6. JTAG Synchronization Circuit

ipg_clk

TCK

sync1

sync2

sync3

tap_enable

dbg_tck_sync

TMS

TDI

dbg_tms_sync

dbg_tdi_sync

MAC7200 Datasheet(PDF) 173 Page - Freescale Semiconductor, Inc