[En-Nut-Discussion] rtl8019as

[Henrik Maier]

Hi Matt!

I have worked with several designs involving the RealTek chip.

AEN must be low as mentioned in RealTek's data sheet for NIC register 
access.

IOCS16B is an input during reset then becomes an open drain output.

IOCS16B MUST be at a logic low level for 8 bit designs during reset. 
Refer to RealTek data sheet.

IOCS16B is usually tied to ground via a 27K resistor. However one can 
spare the resistor and tie it directly to GND because after reset it 
becomes an open drain output. The 27K resistor is a legacy of the PC's 
ISA bus.

Here is a quote from RealTek's support on this matter:
"Q: Does IOCS16B need to be connected or can it be left open (no ISA
bus available)?
A:  I suggest you could pull high 300 Ohm and pull low 27K in IOCS16B.
"


Regards

Henrik Maier
-- 
FOCUS Software Engineering Pty Ltd
Brisbane, Australia - Web: www.focus-sw.com
Phone: +61-402 970 933 - Fax: +61-7-3009 0399

Matt Bell wrote:
> Hi,
> 
> When using the RTL8019AS ethernut controller is it absolutely necessary
> to tie both pins AEN and IOCS16B to ground when using it the same way
> its wired in the ethernut 1.3-F board?
> 
> Thanks,
> -Matt
> 
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