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Forum: FPGA, VHDL & Verilog Extending the T51 IP core with SFR peripherals to a 80C522


von Pascal (Guest)


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Hello,

Many people write that it is quite easy to add additional peripherals to
the T51 core by means of the SFR bus.

Are there any VHDL examples out there on the net? =)

Reason why I am asking: I want to extend/modify the T51 IP core to make
the 8052 into a 100% compatible NXP 80C522 microcontroller.

As you might know, this means: 1) I2C, 2) Compare registers, 3) PWM,
etc.

The extended T51 should be 100% compatible with the 80C522, meaning that
the original ROM code should run flawless.

Adding a peripheral to the SFR bus might be easy, but if so, how come
that there are no concrete VHDL examples for the T51 IP core in
particular.

Additional question: If you add a peripheral by means of Wishbone, does
the microcontroller code need to know about the peripheral bus, or would
it work in similar way as if it was connected to the Intel SFR bus? It
looks like using the Wishbone bus, would mean customer microcontroller
code, therefore I prefer to stick with the original SFR bus, as that was
designed exactly for the purpose to have a common 8051 core, and extend
the core to its own flavour while staying compatible...

But again.. then I would like to have some example.

Is there anybody out there who did a similar project like the one I
suggested.. e.g. converting T51 8052 into a 80C522 microcontroller IP
core =)

BTW. It's totally okey to write back in German if that is easier for
you. I do understand german.

Thanks for your help,

/Pascal

: Moved by Admin
von chris (Guest)


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I have made similar things in past.
My base was a 8031 verilog source, that i converted to 8032 source,
and then extended to the needed peripherials.
The project required the same timing as the orginal chip.
I doubt, that with the T51 implementation you will be 100%
compatible with the orginal chip and timing cycles.

von Pascal (Guest)


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Hello,

The most important thing is code compatibility.
Timing less important.


Did you add the peripherals by means of the SFR bus?

Any examples left? or do you have some good application note/reference 
document/tutorial to add peripherals to the SFR bus?

Any help appreciated!

Thanks,
/Pascal

von chris (Guest)


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Hi,
because i don´t have used the T51 branch, i could not helping with it.
I have some examples of adding I2C and PWM to the 8051 from the
University of California if this could help, but it don´t help if you
want use the T51.

Regards
Chris

von Pascal (Guest)


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Hello,

Thanks for your feedback.

Does the Dalton 8051 support SFR bus or did you add peripherals in 
different way to the main core?

Thanks,
/Pascal

von chris (Guest)


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Usually, if the core have a dedicated SRF bus, then you must make a
write decoder and a read multiplexer for accessing the user supplied
periferial extension. This components are not needed, if the core
is used without user extension. Maybe this is the info you miss.
Further, depending on the implementation, there may be different
signals for the bus read cycle, if the operation is read only or 
read-modify-write.

von Pascal (Guest)


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Hello,

About the examples for adding I2C and PWM to the Dalton 8051.
Can you provide this code?

I want to add similar to the Open Cores T52: 8052.

Thanks,
/Pascal

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