Um,

Do we have confusion on the meaning of the term 'unbanked' here?

It seems that some might think unbanked ram is ram that is only valid with a 
single setting of the RP0/1 bits.

Others might think unbanked ram is accessible regardless of the setting of 
the RP0/1 bits.

And then of course it seems this chip has 'semibanked' ram which is 
accessible with two different settings of the RP0/1 bits. :)


Bob Ammerman
RAm Systems



----- Original Message ----- 
From: "Jan-Erik Soderholm" <jan-erik.soderholm@telia.com>
To: <piclist@mit.edu>
Sent: Wednesday, March 09, 2005 6:05 AM
Subject: RE: [PIC] MPLAB Linker script and Datasheet for 16F870 don't match, 
any ideas why?


> Vincent Vega wrote :
>
>> Hello Jan-Erik,
>> I didn't understand what you meant with the *single* bank stuff.
>
> I ment that there is no single RAM/GPR location that is *only*
> accessable from a *single* bank (not counting the SFRs, of course !!)
>
>> Where in the datasheet did you find that all RAM locations
>> are accessible from 2 or 4 Banks?
>
> Figure 2-2, page 12 in DS30569A.
> I'm currently downloading the rev-B version, just to check......
> ...... nop, it's the same in Rev-B. Same fig on the same page no.
>
>> Why do we need then STATUS,RP0 and STATUS,RP1?
>
> To change bank, when needed. I don't think I understand
> the question.
>
>> Since all RAM allocations are accessible from at least two
>> banks, can you explain the following?
>> How can you access the general purpose registers ( 0xA0 to
>> 0xBF)on Bank1 on the PIC16F870 without switching banks?
>
> If you're in bank 1 or 3, you don't have to.
> If you're in bank 0 or 2, you have to change to bank 1 or 3...
>
>> or perhaps, while in Bank0 how would you change the
>> contents of any of the TRIS register without changing banks?
>
> Now, *I* have only been talking about the RAM/GPR's. I'm
> sorry if there was any missunderstanding there ! The SFR's
> are handles through the four DATABANK's "sfr0" - "sfr3".
>
>> This is breaking news for me, I'm very glad now we can get
>> rid off the bank
>> switching for the mid range pics, but OK if you can show me.
>
> Very funny... :-)
>
>> There's nothing wrong with the template,..
>
> If you say so, I havn't checked the template.
> I was just pointing out that there isn't anything wrong with
> the LKR, at least not when compared with the data sheet.
>
> Best Regards,
> Jan-Erik.
>
>
>
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