Lpc2000

Rob,

Thanks. 

George

On Sun, 2006-01-08 at 10:01 +0100, Rob Jansen wrote:

> George,
> 
> The I/O pins are 5V tolerant and the I2C pins have open drain outputs.
> So  to  answer Q1: You may pull the pins to 5 volt, creating a 5 volt 
> I2C interface for your PICs.
> 
> An answer on Q2 depends a bit on the type of cable used in
> combination 
> with bus termination.
> I do not think however that a100 or 400 kHz clock will be a problem.
> If you are woried about bus errors, check the amount of traffic that 
> passes over the bus and the response times you need and  adapt your 
> clock to be the lowest allowable value. I.e: if writing an output to
> the 
> PIC needs 5 bytes (slave addr + 4 data) this uses 47 clocks (start bit
> + 
> 4x9 + stop bit) and if this needs to complete within 10 ms which
> results 
> in a 4.7 kHz clock (3 of these on one bus result in 14.1 kHz).
> 
> Regards,
> 
>     Rob
> 
> 
> George M. Gallant, Jr. wrote:
> 
> >I want to add a lpc2214 to an existing robot that currently has 3
> >18f252's connected via
> >I2C. The LPC would become that MASTER and the PIC's become
> peripherals.
> >The PIC's
> >are at 5V due to external sensors and control circuits. 
> >
> >Questions: 1. What voltage shoudl the SDA & SCL be pulled up to?
> >                  2. Max clock rate for 10inch (25cm) cable?
> >  
> >
> 
> 
> 
> 
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