Hello,David,
I don't konw which schematic you are reading, but normally:
>>PWM1 (pin 37) - what does this do?
this is PWM signal. there are more 2 PWM modules in i.MX SoC.
>>DRDY (pin 34) - is this Data Enable?
This is data enable signal.
>>CNTRST (pin 4) - this sounds like "contrast": is it a PWM signal?
Yes, it is PWM signal. used to control back light of LCD.
Regards,
Weidong