Re: RTL8019AS 16bit mode

Jan Dubiec wrote:
> I have built a device based on Renesas' H8/3068F and RTL8019AS. I have
> connected the chips in the following way:
> H8/3068F   RTL8019AS   Notes
> --------   ---------   -----
> A[0-9]     A[0-9]      other Realtek's address lines tied to GND
> D[8-15]    SD[0-7]     D8<->SD0, D9<->SD1, etc.
> D[0-7]     SD[8-15]
> /CS4       AEN
> /HWR,/LWR  IOWB        connected through HC08 (AND) gate
> /RD        IORB
> /WAIT      IOCHRDY     line pulled up through 10k
> /IRQ0      INT0
>            SLOT16      pulled down though 27k

In my experience, it's all in the software, and DCR bit 0 (WTS) is the
key.  I've left IOCS16 (SLOT16) floating with no effect (as have other
designs).  With as little as A[0-4], SD[0-15], IOWR, IORD, IOCHRDY
you're good to go.

Registers use 8-bit access regardless.  Have you tried your test with
the buffer ring instead?  Have you just tried a regular transmission,
sending 16 bits per I/O instead of 8?

As for init, the DCR value gets set immediately after after stopping the
NIC for 1.6mS to reset it.  Are you stopping the NIC first during init,
and are you waiting the spec 1.6mS before proceeding?


FYI, some suggestions to save MCU pins: you only need the lower 5 pins
to address the 8019AS; you can hardwire the rest unless you're using a
shared address bus.  Likewise, AEN can be wired low.  As long as you
don't strobe IORD or IOWR, you can share all the SA and SD lines with
other purposes.

For some schematics, you could check out the AVR implementation of the
RTL8019AS at http://www.picoweb.net among many others.  However, you'll
find that many implementations omit CHRDY wiring, which is hazardous.

http://www.edtp.com may also be a useful reference, as they sell 8019AS
proto boards.