Chapter 4
Programming
© National Instruments Corporation
4-53
AT-MIO-16D User Manual
Sample Counts 2 through 65,536. To program the sample counter for sample counts up to
65,536, use the following programming sequence. The minimum permitted sample count is two.
All writes are 16-bit operations. All values given are hexadecimal.
a. Write FF04 to the Am9513A Command Register to select the Counter 4 Mode Register.
b. Write 9025 to the Am9513A Data Register to store the Counter 4 mode value.
c. Write FF0C to the Am9513A Command Register to select the Counter 4 Load Register.
d. Write the sample count value to the Am9513A Data Register to store the Counter 4 load
value:
•
If the sample count is between 2 and FFFF (65,535 decimal), write the sample count to
the Am9513A Data Register.
•
If the sample count is 10000 (65,536 decimal), write 0 to the Am9513A Data Register.
e. Write FF48 to the Am9513A Command Register to load Counter 4.
f.
Write FFF4 to the Am9513A Command Register to decrement Counter 4.
g. Write FF28 to the Am9513A Command Register to arm Counter 4.
h. Clear the 16*/32 CNT bit in Command Register 1 to notify the hardware that only Counter 4
will be used as the sample counter.
After you complete this programming sequence, Counter 4 is configured to count A/D
conversion pulses generated by Counter 3 and turns off the data acquisition operation when
Counter 4 decrements to zero. Counter 4 begins counting A/D conversion pulses when a rising
edge signal is received on the STOP TRIG input. A/D conversion data stored before receipt of
the STOP TRIG signal are pretrigger samples.
Sample Counts Greater Than 65,536. To program the sample counter for sample counts greater
than 65,536, use the following programming sequence. The lower 16 bits of the sample count
are stored in Counter 4, and the upper 16 bits of the sample count are stored in Counter 5. All
writes are 16-bit operations. All values given are hexadecimal.
a.
Write FF04 to the Am9513A Command Register to select the Counter 4 Mode Register.
b.
Write 9025 to the Am9513A Data Register to store the Counter 4 mode value.
c.
Write FF0C to the Am9513A Command Register to select the Counter 4 Load Register.
d.
Write the least significant 16 bits of the sample count value minus 1 to the Am9513A Data
Register to store the Counter 4 load value.
•
If the least significant 16 bits are all zeros, write FFFF.
e.
Write FF48 to the Am9513A Command Register to load Counter 4.
f.
Write 0 to the Am9513A Data Register to store 0 into the Load Register for Counter 4
reloading.
Содержание AT-MIO-16D
Страница 16: ......
Страница 23: ......
Страница 185: ......
Страница 206: ......
Страница 207: ......
Страница 208: ......
Страница 209: ......
Страница 210: ......
Страница 211: ......
Страница 212: ......
Страница 213: ......
Страница 214: ......
Страница 215: ......
Страница 216: ......
Страница 217: ......
Страница 218: ......
Страница 219: ......
Страница 220: ......
Страница 221: ......
Страница 222: ......
Страница 223: ......
Страница 224: ......
Страница 225: ......
Страница 226: ......
Страница 227: ......
Страница 228: ......
Страница 229: ......
Страница 230: ......
Страница 231: ......
Страница 232: ......
Страница 233: ......
Страница 234: ......
Страница 235: ......
Страница 236: ......
Страница 237: ......
Страница 238: ......
Страница 239: ......
Страница 240: ......
Страница 241: ......
Страница 242: ......
Страница 243: ......
Страница 244: ......
Страница 246: ......
Страница 247: ......
Страница 248: ......
Страница 249: ......
Страница 250: ......
Страница 251: ......
Страница 252: ......
Страница 253: ......
Страница 254: ......
Страница 255: ......
Страница 256: ......
Страница 257: ......
Страница 258: ......
Страница 259: ......
Страница 260: ......
Страница 261: ......