Independent processes

[john]

Hello,

I have interfaced a 8 bit parallel data bus and a clock signal of the
USB device to a CPLD. I need to store 32bits of data in a buffer. And
then serially shift out the 32 bits. The loading of the data into the
buffer can only be done by using the clock coming from the USB device
because when USB generates data it generates clock with it. So I
decided to use another clock to serial out the data. The problem is the

handshaking between the USB process and the serial out process. The two

processes have different clocks so the serial out process could miss
the signal form the USB process that the buffer is ready to be serial
out. The USB device only provides clock and the data, no hand shaking
signals.

Please advice a solution, thanks


John

 

[Mike Treseler]

I have interfaced a 8 bit parallel data bus and a clock signal of the
USB device to a CPLD.

I liked Ray's answer:

http://groups.google.com/groups?q=fpga+usb_clk+toggle_ff

 

[john]

Hi,

Thanks for the reply! But do not have "we" signal or input pin
available. Please advice.

John

 

[john]

Hi,

Thanks for the reply! But do not have "we" signal or input pin
available. Please advice.

John