[En-Nut-Discussion] TWI aka I2C, not getting an ACK back?

[Douglas Pearless]

There are only two 2k2 pull ups on SDA and SCK to +5v and the DS1337.  
There are no other wires or connections!

Cheers Douglas

Harald Kipp wrote:

> Hi Douglas,
>
> At 16:30 16.03.2005 +1300, you wrote:
>
>>    rc = writeRTC(sla,0x0E,dataRTC,2); //on the i2c bus I get "<start> 
>> 110100000 <SDA goes high>  000000000  000000000 000000000<stop>
>> //where did the 0x0E go which should have been immediately after <SDA 
>> goes high>
>> //I checked the wrteRTC routine and it does pass 0x0E 0x00 0x00 in 
>> the 'data field to TwMasterTransact
>
>
> What about hardware? You are aware, that I2C is open
> drain? Did you add pull-ups? Anything else connected,
> which may drive the bus low?
>
> Harald
>
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