MVME5100 Single Board Computer Programmer's Reference Guide

32-Bit Counter
Address $FEF80100
Bit
External Register Set
Programming Model
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Name CTR32
Operation READ/WRITE
Reset 0 PL
CTR32 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 frequency, 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.
Address $FEF88000 - $FEF8FFF8
Bit
Name
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
EXTERNAL REGISTER SET
Operation READ/WRITE
Reset X PL
EXTERNAL REGISTER SET The EXTERNAL REGISTER SET is user provided and
is external to the Hawk. It is enabled only when 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.
http://www.motorola.com/computer/literature 3-73
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