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Zone selection in TMS320F28335

Ankit Gupta6
Intellectual 565 points

Other Parts Discussed in Thread: TMS320F28335

HI,

I am new to coding and have some basic doubts. 

I am developing a code to interface TMS320F28335 with MAX2982.

I plan to use the Zone 7 available XINF for this purpose. Using example codes i am able to initialize zone 7 as per my requirements but i am a bit confused in how do i tell the CPU that i have selected zone 7? is there a zone select register ?

Also, i need to write an address in the address bus to select proper external device. Should i write using pointers in the address bus register or is there some other easy way for it?

 

  • 0
    TI__Guru** 117261 points
    Ankit,

    All XINTF zones have specific address and based on the address CPU will send access to XINTF module and XINTF module furthers decodes these address to activate particular chip select. E.g. address for Zone 7 is "0x0020-0000 - 0x002F-FFFF" so any read/write access with-in this address range will activate Zone 7 chip select. You have to use pointers to read/write to external device.

    Regards,
    Vivek Singh
  • 0 in reply to Vivek Singh
    Intellectual 565 points
    Thank you Vivek,

    1) As per my understanding , Address bus is a output bus by which i can select which external device is to be selected. (am i right?)

    2) I have defined GPIO pins as XA [19,0]. should i write the address directly on these using GPIOset/reset? Also, it is a 20 bit address bus how should i write a 32 bit address on it?
  • 0 in reply to Ankit Gupta6
    TI__Guru** 117261 points

    Ankit,

    1) As per my understanding , Address bus is a output bus by which i can select which external device is to be selected. (am i right?)

    Output address bus does not select the external device. Output address bus connect to all the external device. Chip select signal selects external device hence each zone has it's own chip select signal.

    2) I have defined GPIO pins as XA [19,0]. should i write the address directly on these using GPIOset/reset? Also, it is a 20 bit address bus how should i write a 32 bit address on it?

    No, you don't have to write the address value on the address bus. It's driven by XINTF module based on the CPU read/write access. Please refer the example code to see how read/write access to external device are initiated.

    Regards,

    Vivek Singh