SERIES AP48X ACROPACK
USER
’S MANUAL
Acromag, Inc. Tel: 248-295-0310
- 48 -
- 48 -
https://www.acromag.com
Table 3.17 Counter Control
Register (Period
Measurement)
1. The default state of the
output pin is high (output has
pullup resistor installed). Bit
3 specifies the active output
polarity when the output is
driven.
Bit(s)
FUNCTION
2,1,0
Specifies the Counter Mode:
110
Period Measurement
3
Output Polarity (Output Pin ACTIVE Level):
0
Active LOW (Default)
1
1
Active HIGH
5, 4
InA Polarity / Signal Measured
00
Disabled (Default)
01
Active LOW starts period measurement.
10
Active HIGH starts period measurement.
11
Disabled
7, 6
InB Polarity / External Clock Input
00
Disabled (Default)
01
External Clock Enabled
10
External Clock Enabled
11
Disabled
9,8
InC Polarity / External Trigger
00
Disabled (Default)
01
Active LOW Trigger
10
Active HIGH Trigger
11
Disabled
12,11,10 Clock Enable Frequency
000
Internal (Default)
1.953125MHz
001
Internal
3.90625MHz
010
Internal
7.8125MHz
011
Internal
15.625MHz
100
Internal
62.5MHz
101
Undefined
N/A
110
External InB
CNTInB
111
External Clock (pin
49)
Up to 15MHz
14 ,13
Not Used (bits read back as 0)
15
Input Debounce Enable
0
Disabled (Default)
–
No Debounce Applied to any
Input.
1
Enabled
–
Reject Gate-Off or Trigger Pulses (noise)
less than or equal to 2.4
s.