Programming Model
http://www.motorola.com/computer/literature 3-73
3
32-Bit CounterCTR32 CTR32 is a 32-bit, free-running counter that increments once per microsecond if the CLK_FREQUENCY register has been programmed properly. Notice that CTR32 is cleared by power-up and local reset.Note When the system clock is a fractional freque ncy, such as 66.67 MHz, CTR32 will count at a fractional amount faster or slower than 1 MHz, depending on the programming of the CLK_FREQUENCY Register.External Register SetEXTERNAL REGISTER SET The EXTERNAL REGISTER SET is user provided and is external to the Hawk. It is enabled only wh en the tben_en bit is cleared. When the tben_en bit is set, the EXTERNAL REGISTER SET is disabled and the Hawk does not respond in its range except for the tben register at $FEF88300.The tben register (which is internal to Hawk) responds only when tben_en is set.
Address $FEF80100
Bit
0
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31
Name CTR32
Operation READ/WRITE
Reset 0 PL
Address $FEF88000 - $FEF8FFF8
Bit
0
1
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31
Name
EXTERNAL REGISTER SET
Operation READ/WRITE
Reset X PL