Re: [ts-7000] query: -on board Xilinx CPLD

[anand bhavnani <>]

As u have mentioned the processor handles flash through the cpld and additionally cpld perfoms several other functions. 

so can i assume that the cpld is on the board primarily because the processor in itself is not having a controller (like uart controller,VEC. INT. ,...etc) that could have effectively interfaced with the flash and hence the need for cpld arose.

also please suggest a DAC  that i may use to provide the sound support to the board considering the fact that i am using MAX197 12 bit ADC.

thanks,
//anand.

Curtis Monroe <> wrote:
>      The CPLD is used to control the NAND flash. By setting registers in the CPLD 
>  you can set the ALE and CLE control lines for the flash. Another register on 
>  the CPLD tells you if the NAND is busy or not. (its busy when its writing or 
>  era!
>  sing
>  pages, or preparing a page to read)
>  
>  The CPLD also converts the SRAM bus control signals to RD, WR, and CS signals 
>  for flash. 
>  
>  The CPLD does more than just NAND flash management. It also:
>        - handles control signals on the PC104 bus, 
>        - has a watchdog timer, 
>        - lets you read the jumper settings,
>        - does some stuff with UART2
>        - handles the rest button
>        - handles the voltage supervisor to delay bringing the EP9302 out of reset 
>  till the power has settled.
>        - interfaces to the Real time clock
>        - controls the EEPROM chip select, (e.g. to turn it off after booting)
>  
>  The one thing I don't understand is; why is the flash connected to the 
>  buffered side of the data bus? and n!
>  ot
>  directly to the controller. I don't 
>  think the capacitance on the bus is more than the 50pF recommended with only 
>  two sdrams. Maybe they wanted to isolate the flash from the data bus so both 
>  buses can operate independently? Maybe routing was easier?
>  
>  -Curtis.
>  
>  
>  On February 9, 2006 10:41 am, anand bhavnani wrote:
>  > Friends,
>  >    
>  >   the 7250 has Xilinx 9572 CPLD on the board. the flash is connected to it.
>  >   can please someone let me know why is it so..
>  >   what is the purpose of cpld..
>  >   also can i do without the cpld, or replace it with some other..
>  >    
>  >   also what equipment(for downloading, specifications) would i need for the 
>  cpld..
>  >    
>  >   good bye,
>  >    
>  >   //anand.
>  > 
>  > 
>  > "Stay HUNGRY. S!
>  tay
>  FOOLISH." Steve Jobs
>  >             
>  > ---------------------------------
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>                 



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