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Chapter 3
Register Details And Use
3.3 MM
-
Master Mode Register (AM 9513)
The MM register is used to enable and perform special
functions common to each of the five counters on the AM 9513
counter chip. This section will describe the meaning of each of
these functions, and how to set the MM register to accomplish
the special function.
The MM register, a 16-bit register divided into seven sections,
is used to enable and assign parameters for the various
functions performed by the MM register. The bit assignments
of the MM register and their meanings are listed below.
Refer to Chapter 4 for setting the MM register with standard
software blocks. The MM register can be set using the PA
mode of FB159. Care must be taken when using the PA mode
because the .MM register is set each time the PA mode is
used for a particular counter.
MM
-
Low Order Byte
Subaddress xxx7, Write
Bit
7
6
5
4
3
2
1
0
...
Pulse Source
for Scaler 2
Time
Clock
1
1
Comparator 1
1
comparator
2
MM
-
High Order
Byte Subaddress m 6 , Write
Bit
15
14
13
12
11
10
9
8
I
Scaling factor Scaler 2
I
Scaler 1
Counting mode
Scaler
2
enable
3.3.1 Real-Time Clock: MM1
-
MM0
The AM 9513 can perform a real-time clock function but this
function is not supported by the 8085 firmware. A custom-
made function block is required to support this feature.
Unless you have created this function block, the value of MM1
and MM0 should be 00 to leave this function disabled.
MM1
MM0
Description
0
0
Real time clock disabled
0
1
Input frequency scaled for 50Hz
1
0
Input frequency scaled for 60Hz
1
1
Input frequency scaled for 100 Hz
3.3.2 Comparators 1 and 2: MM3
-
MM2
The comparator function of the AN 9513 will allow Counters 1
and 2 to perform a 16-bit compare function. The actual value
of the counter is compared to the value stored in the alarm
register for the counter.
Enabling the compare function for the counter will enable
special circuitry in the AM 9513, which will configure the
counter output to go to the active state when the comparison
is true. The comparison is considered trueonly when thevalues
are equal to each other.
When the count value changes from the true state, the output
will again appear in the false state. The active state of the
counter may be set to active high or active low in the CM
register (CM2
-
CMO).
MM3
MM2
Description
X
0
Comparator 1 disabled
X
l
Comparator 1 enabled
0
X
Comparator 2 disabled
1
X
Comparator 2 enabled
X
=
irrelevant
3.3.3 Scaler 2 (FOUT) Pulse Source: MM7
-
MM4
Description of pulse source
Output Scaler 1 F1
Counter input l
Counter input 2
Counter input 3
Counter input 4
Counter input 5
Gate input 1
Gate input 2
Gate input 3
Gate input 4
Gate input 5
Output Scaler 1 F1
Output Scaler 1 F2
Output Scaler 1 F3
Output Scaler 1 F4
Output Scaler 1 F5
NOTE:
The reset or default value for MM7
-
MM4 is
0000.
3.3.4 Scaler 2 (FOUT) Scaling Factor: MM11
-
MM8
The scaling factor of the pulse source signal, which was
@
selected in bits MM7
-
mm4, can now be selected using bits
MM1 1
-
MM8. A scaling factor from 1-1 6 may be selected.
Scaler 2 now scales the selected pulse source by the selected
scaling factor. The results is routed to the output of scaler 2
(FOUT).
Scaling Factor
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
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