Serial EEProm Application

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robismyname

Joined: 17 Jan 2008
Posts: 163
Helped: 2
Location: Central Florida

14 Jul 2009 17:13 eeprom application

Can someone please help me interpret the 8K-bits EE prom option on page 5 of the attached schematic.

Here are some of my questions:

1) Why is there a 0 ohm resistor going to ground?
2)Pin 6 and 5 are connected to what?
3)why is A0,A1,A2 connected to ground?
4) Why are there not bypass caps on VCC?
5) What is the value of R9?
6) Why is pin 7,6,5 connected to power?
7) What does DNS mean?

Im using this schematic as a reference for my own design and just wanted to get a feel for what is being done.

Any help is appreciated.

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ep20k

Joined: 17 Sep 2002
Posts: 319
Helped: 15

14 Jul 2009 21:36 eeprom app.

Hi robismyname

1: You are able to write

2: I²C

3: Defines I²C-address

4: There is C23

5: Just pads, not equipped

6: They are not, have a closer look Very Happy

7: See point 5

Best regards,

ep20k

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robismyname

Joined: 17 Jan 2008
Posts: 163
Helped: 2
Location: Central Florida

17 Jul 2009 16:19 dns do not stuff

ep20k wrote:

ep20k

Is an FPGA a I2C device?

So R9 is just a pad? Why didn't they just type PADS instead of DNS? What does DNS actually mean?

R10 is connected to pin 5 on one side but what is it connected to on the other side? I see 1.8V_BD isn't that power?

R11 is connected to pin 6 on one side but what is it connected to on the other side?
I see 1.8V_BD isn't that power?

wade_hassler

Joined: 07 Aug 2008
Posts: 13
Helped: 3

17 Jul 2009 19:20 serial eeprom application

DNS means 'do not stuff.' an instruction to the PC board maker.
It can also appear as DNP ('do not populate') which makes a bit more sense on a surface-mount board

ep20k

Joined: 17 Sep 2002
Posts: 319
Helped: 15

17 Jul 2009 22:18 Re: Serial EEProm Application

robismyname wrote:

Is an FPGA a I2C device?

You can make it an 'I2C device', have a look at the opencores side.

robismyname wrote:

So R9 is just a pad? Why didn't they just type PADS instead of DNS? What does DNS actually mean?

No it is R9 without the resistor. It is not helpfull to start your design with a write protected EEPROM. Later you can equip the PCB with a programmed PROM and R9.

DNS Question

maybe 'do not supply'

robismyname wrote:

R10 is connected to pin 5 on one side but what is it connected to on the other side? I see 1.8V_BD isn't that power?

yes

robismyname wrote:

R11 is connected to pin 6 on one side but what is it connected to on the other side?

robismyname

Joined: 17 Jan 2008
Posts: 163
Helped: 2
Location: Central Florida

18 Jul 2009 4:25 Re: Serial EEProm Application

ep20k wrote:

robismyname wrote:

R10 is connected to pin 5 on one side but what is it connected to on the other side? I see 1.8V_BD isn't that power?

yes

robismyname wrote:

R11 is connected to pin 6 on one side but what is it connected to on the other side?

i see R11 connected to pin 6 on one side and 1.8V_BD on the other side. It looks the same as R10 so I would think the answers would be the same(r10 and r11 connected to power.

The datasheet says the data pin sda is pulled high. Doesn't the clock pin scl need to be set high in order to toggle?

THe datasheet says A0 ans A1 are no connects and A2 is used for hardwire addressing. Well if A2 is used for hardwire addressing why is it connected to ground in the schematic?

please help

ep20k

Joined: 17 Sep 2002
Posts: 319
Helped: 15

18 Jul 2009 11:34 Re: Serial EEProm Application

robismyname wrote:

R10 and R11 are the pull-ups for clock and data lines of the I2c-bus. So both lines are set high. It is just fine.

robismyname wrote:

THe datasheet says A0 ans A1 are no connects and A2 is used for hardwire addressing. Well if A2 is used for hardwire addressing why is it connected to ground in the schematic?

See figure 7 of the datasheet.

ep20k