4.4.1. Global Timer Counter Registers, 0x00 and 0x04

There are two timer counter registers. They are the lower 32-bit timer counter at offset 0x00 and the upper 32-bit timer counter at offset 0x04.

You must access these registers with 32-bit accesses. You cannot use STRD/LDRD.

To modify the register proceed as follows:

  1. Clear the timer enable bit in the Global Timer Control Register

  2. Write the lower 32-bit timer counter register

  3. Write the upper 32-bit timer counter register

  4. Set the timer enable bit.

To get the value from the Global Timer Counter register proceed as follows:

  1. Read the upper 32-bit timer counter register

  2. Read the lower 32-bit timer counter register

  3. Read the upper 32-bit timer counter register again. If the value is different to the 32-bit upper value read previously, go back to step 2. Otherwise the 64-bit timer counter value is correct.

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