cosmicboy
Junior Member level 2
xc9536 pinout
Hi folks,
I am working on a simple 7 segment clock project using a XC9536 CPLD by Xilinx. I have some experience with microcontrollers but this is the first time I will be using a CPLD so please be gentle
To generate the timebase I figured the easiest option would be to use a standard 32.768kHz watch crystal and divide it to acquire the 1Hz however I am slightly confused by the pin assignments for the external clocks. On a simple microcontroller system I would just use the OSC1/OSC2 pair to hook up the crystal but I couldn't see a similar arrangement in the pinout descriptions for the XC9536. To add to my confusion, I have found this bit of circuitry and I can't make any sense out of it:
**broken link removed**
A NAND gate?? Can't I just use the crystal on it's own? (with loading caps)
The other problem is how do I actually divide the clock? I am planning to use VHDL so would it be simply "wait for 1ns" between my instructions?
I am slightly confused and would appreciate if you could shed some light
Thanks a lot!
Hi folks,
I am working on a simple 7 segment clock project using a XC9536 CPLD by Xilinx. I have some experience with microcontrollers but this is the first time I will be using a CPLD so please be gentle
To generate the timebase I figured the easiest option would be to use a standard 32.768kHz watch crystal and divide it to acquire the 1Hz however I am slightly confused by the pin assignments for the external clocks. On a simple microcontroller system I would just use the OSC1/OSC2 pair to hook up the crystal but I couldn't see a similar arrangement in the pinout descriptions for the XC9536. To add to my confusion, I have found this bit of circuitry and I can't make any sense out of it:
**broken link removed**
A NAND gate?? Can't I just use the crystal on it's own? (with loading caps)
The other problem is how do I actually divide the clock? I am planning to use VHDL so would it be simply "wait for 1ns" between my instructions?
I am slightly confused and would appreciate if you could shed some light
Thanks a lot!