CMOS level on DIO-32HS?

[latinarebelde]

Hi,
I have worked with the DIO-32HS card but always use the TTL level. My next project requires me to use the CMOS level (2.4V). I know the card is compatible for this (from manual). What do I need to do to output this level? Is it hardware or software that I need to change? Thank you for your help.

[tnewton]

You don't set anything. The only reason it's 'compatible' is because of the acceptable input or output levels. There are TTL compatible CMOS families, which are no problem. Otherwise, you have to make sure that you can drive the specified level. Comparing the specs for TTL and CMOS (32HS is TTL)


Vin(low_max) :TTL = .8V
CMOS = .9/1.35 (depends on family)
Vin(high_min):TTL = 2.0V
CMOS = 3.15V

Vout(low_max) :TTL = .4V
CMOS = .1V
Vout(high_min):TTL = 2.4V
CMOS = 4.4V

By looking at the above, you can see if a TTL output can drive a CMOS input and vice versa. A CMOS output can completely drive a TTL input, low and high. If you are taking inputs with the 32HS, no problems. However,
CMOS input levels are only TTL low-level compatible. To output from the 32HS to CMOS inputs, consider these options
1. pull-up resistor to bring output to CMOS levels
2. driver IC's to convertTTL to CMOS
3. use TTL-compatible CMOS(name ends with 'T',like ACT)