ADLINK cPCI-8554/R - Manual (Page 42)

32 • Signal Connection and Applications
4.4 Frequency Generator
4.4.1 To generate a 250 KHz Square Wave.
Step 1: Use a fixed clock source because the output is a fixed
frequency.
Step 2: The internal 8MHz clock is capable of generating the
250KHz frequency. Use Counter 1 for this application.
∴ 250 kHz = 8MHz/32
Step 3: The gate source should be set to “enable” always and
therefore GATE1 is let open (pin 99 of CN1).
Step 4: Connect the counter output to an external device and
write the control program. Refer to ‘DEMO1.C’
source code.
COUT1
Counter #1
8254 Chip #1
C
G
O 'H'
ECK1
GND
CK1
COUT10
8MHz
COUT11
set by function "8554_SET_cntCLK"
set by function
"_8554_SET_CK1"
Figure 20: Example of a frequency generator (1)