pnx1500 NXP Semiconductors, pnx1500 Datasheet - Page 751

• Manufacturer Part Number: pnx1500
• Description: Pnx15xx Series Connected Media Processor
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Volume 1 of 1
PNX15XX_SER_3
Product data sheet
3.1.1 Handshaking and Communication Protocol
The following describes the mechanism for transferring data via JTAG.
Transfer from Debug Front-End to Debug Monitor
The debugger front-end running on a host transfers data to a debug monitor via the
TM_DBG_DATA_IN register. It must poll the TM_DBG_CTRL2.ifull bit to check if the
TM_DBG_DATA_IN register can be written to. If the TM_DBG_CTRL2.ifull bit is clear,
the front-end may scan data into the TM_DBG_DATA_IFULL_IN register.
Note that data and control bits may be shifted in with SEL_IFULL_IN instruction and
the bit shifted into TM_DBG_CTRL2.ifull register must be 1. This action triggers an
interrupt. The debug monitor must copy the data from TM_DBG_DATA_IN register
into its private area when servicing the interrupt and then clear the
TM_DBG_CTRL2.ifull bit. This allows the JTAG interface module to write the next
piece of data to the TM_DBG_DATA_IN register.
Transfer from Monitor to Front-End
The monitor running on TM3260 must check if TM_DBG_CTRL1.ofull is clear and if
so, it can write data to TM_DBG_DATA_OUT. After that, the monitor must set the
TM_DBG_CTRL1.ofull bit. The debugger front-end polls the TM_DBG_CTRL1.ofull
bit. When set, it can scan out the TM_DBG_DATA_OUT register and clear the
TM_DBG_CTRL1.ofull bit. Since TM_DBG_DATA_OUT is read-only via JTAG, the
update action at the end of scan out has no effect on TM_DBG_DATA_ OUT. The
TM_DBG_CTRL1.ofull bit however, must be cleared by shifting in the value 1.
Controller States
In the power on reset state, TM_DBG_CTRL2.ifull, TM_DBG_CTRL1.ofull and
TM_DBG_CTRL1.sleepless bits are cleared.
Example of Data Transfer via JTAG
Scanning in a 5-bit instruction will take 12 TCK cycles from the Run-Test/Idle state:
Likewise, scanning in a 32-bit data register will take 38 TCK cycles, and transferring
an 8-bit TM_DBG_CTRL data register will take 14 TCK cycles from Idle state.
However, if a data transfer follows instruction transfer, then the transition to DR scan
stage can be done without going through Idle state, thereby saving 1 cycle.
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4 cycles to reach Shift-IR state
5 cycles for actual shifting in
1 cycle to exit1-IR state
1 cycle to update-IR state,
1 cycle back to Run-Test/Idle state.
Rev. 3 — 17 March 2006
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Chapter 24: TM3260 Debug
PNX15xx Series
24-5