I've two question about using Turbo C++ programming to control a hardware which is a 12-bit ADDA (analog-to-digital) card
1. I use a function "outport()" to output a byte to the DA output port like this:
where 0x27F and 0x27E is the I/O port address for output DA high byte and low byte data respectively.
I cannot adjust the output ampitude( voltage ). I have tried to put different value e.g 0x01, 0x0f, 0xff, ... to the output port, but the output ampitude is almost the same. How can I do to adjust the output value? How can I keep the output steady, like a DC output? Any code can be provided to explain?
For more information about the hardware, see attachement(128.zip) P. 11 -2 Digital to analog (D/A) procedure.
Thanks and regards