ARM ARM DUI 0224I manual Reset, DnTRST pulse

Models: ARM DUI 0224I

1 402
Download 402 pages 14.06 Kb
Page 384
Image 384

RealView Logic Tile

F.3.6 Reset

A user design in a RealView Logic Tile can reset the PB926EJ-S by driving the nSRST signal LOW. This has the same effect as pushing the reset button and forces the reset controller to the level specified by the SYS_RESETCTL register (see also, Reset Control Register, SYS_RESETCTL on page 4-31). nSRST is synchronized by the reset controller and can be driven from any clock source. It must, however, be driven active for a minimum of 84ns (two cycles of 24MHz) to ensure that it is sampled by the reset controller. In order to avoid a deadlock condition, the user design must stop driving the nSRST signal after nRESET is asserted.

nSRST is active low and open-drain. It is shared with the JTAG interface and must not be driven to HIGH state. A resistor on the PB926EJ-S pulls the signal HIGH.

The RealView Logic Tile also uses the nPORESET signal to generate a local

D_nTRST pulse.

The GLOBAL_DONE signal is held LOW until the FPGA on the RealView Logic Tile has finished configuration. The system is held in reset until this signal goes HIGH.

F-14

Copyright © 2003-2010 ARM Limited. All rights reserved.

ARM DUI 0224I

Page 384
Image 384
ARM ARM DUI 0224I manual Reset, DnTRST pulse