[En-Nut-Discussion] How Ethernut 1.3-Rev. G hardware works?

[Janusz U.]

> So, when the external RAM is enabled A15 is LOW, so, SA15 is high. What
> append to the RTL when SA15 is high?

when SA15=1 when RTL is not selected I think.

>>RTL has an INTERNAL ADDRESS DECODER for address range 0x0300-0x031F.
> Therefore A15 is inverted...
>
> 0x0300: 11/0000/0000
> 0x031F: 11/0001/1111
>
> What's the goal of having A8 et A9 high?
> I can't find anywhere in the datasheet some information about this 
> INTERNAL
> ADDRESS DECODER... Maybe at the page 19 the bit 3-0 IOS 3-0, we see that 
> the
> I/O Base address is 300H if IOS3=IOS2=IOS1=IOS0=0 BUT I'm not sure if it's
> related to the INTERNAL ADDRESS DECODER?

http://www.m6117d.com/doc/rtl8019.pdf page 32, "The entire range between 
200H and 3FFH is available", it is Plug&Play device, you can configure it 
and save the configuration into EEPROM.

> Could you explain how the RTL8019AS is initialized, please? The RTL is in
> jumper mode so normally, in this mode, the default values of the ressource
> configuration informations which are stored in the CONFIG3-0 registers in
> Group1 Page3 come form the states of jumper pins (cf. p27 in DS) BUT not
> from the 9346. So, when do you read the content of 9346? It's confusing!

I'm no expert for that so I'll avoid the answer.

> Thank you for your help. I hope I'm not too boring with all my stupid
> questions..

As somebody has noticed there is no stupid questions - only stupid answers:)

best rgs
Janusz