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Re: [Discuss-gnuradio] Multiple I2C devices on Rx daughtercards
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] Multiple I2C devices on Rx daughtercards |
Date: |
Mon, 11 Jan 2010 13:04:25 -0800 |
User-agent: |
Mutt/1.5.20 (2009-08-17) |
On Mon, Jan 11, 2010 at 10:51:09AM -0600, John Orlando wrote:
> Hi Matt,
> In reviewing the schematic of the dbsrx daughtercard, I noticed that there
> are two i2c devices (the EEPROM and the MAX211x receiver chip). In general
> for the daughtercards, address bit A1 determines side A or side B, and A0
> determines if the card is an rx or tx card, and this is hard-coded by the
> USRP itself. So...if a user has two dbsrx cards in their USRP, I think the
> EEPROM of the dbsrx on side A would have the same address as the MAX211x on
> side B, and vice versa. Wouldn't this be an issue?
> Also, is there a reason that address bit A2 isn't used to select different
> i2c devices on the same card?
I2C devices have a 7-bit address. Some of them are fixed depending on
the device. E.g., on the 24LC024, the top 4-bits are 1010, which is
different from the bits hardwired into a low speed A/D, D/A, etc.
Take a look at the datasheets.
Eric