ARM ARM DUI 0224I manual 6 100Hz Counter, SYS100HZ, Configuration registers SYSCFGDATAx

Models: ARM DUI 0224I

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Programmer’s Reference

4.3.6100Hz Counter, SYS_100HZ

The SYS_100HZ register at 0x10000024 is a 32-bit counter incremented at 100Hz. The 100Hz reference is derived from the 32KHz crystal oscillator. The register is set to zero by a reset.

4.3.7Configuration registers SYS_CFGDATAx

The read/write registers SYS_CFGDATA1 and SYS_CFGDATA2 contain configuration data that is applied to the ARM926EJ-S PXP Development Chip HDATAM1 and HDATAM2 pins when the DEV CHIP RECONFIG pushbutton is pressed.

In a production ASIC, the configuration signals would be tied HIGH or LOW, but they are configurable in the ARM926EJ-S PXP Development Chip. This enables you to test different build options. For example, you can simulate a system that boots in big-endian or with the vector table located at address 0xFFFF0000 by changing the value of bits 0 and 1 in the SYS_CFGDATA2 register and pressing the SDC RECONFIG button.

For details on the configuration process, see Configuration from the DEV CHIP

RECONFIG pushbutton on page 3-9.

SYS_CFGDATA1 at address 0x10000028 contains the configuration settings to apply to HDATA1 pins and the clock multiplexing logic. Figure 4-10 and Table 4-8 on page 4-26 show the configuration signals for each bit and the default value loaded at power on reset.

Figure 4-10 SYS_CFGDATA1

ARM DUI 0224I

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

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Page 191
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ARM ARM DUI 0224I manual 6 100Hz Counter, SYS100HZ, Configuration registers SYSCFGDATAx