Message

Reply | Reply all

Date Prev | Date Next | Thread Prev | Thread Next Date Index | Thread Index

From: Mikhail Matusov<misoma@r...>
Date: Mon Mar 26 17:21:44 CEST 2007
Subject: [oc] I2C Open Drain VHDL Implementation
On Mon, 26 Mar 2007 01:46:02 -0400 (EDT)
"D R" <heedaf@e...> wrote:

> How do I implement the open drain and how is the line pulled to VCC?

in VHDL:

output_pin <= '0' when desired_output = '0' else 'Z';

As someone has already mentioned, an external resistor is usally used
for the pullup. Most of the FPGAs have internal pullups you could try
using but they are usually too weak for I2C.

/Mikhail