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[SOLVED] How to use bidirectional IO, need it for I2C?

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Hm, you are right. Apparently, some compilers allow mixing...
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The style may be actually accepted by the compiler. But sometimes syntax errors cause irregular error messages.
 
FvM said:
The style may be actually accepted by the compiler. But sometimes syntax errors cause irregular error messages.
Click to expand...
Interesting conclusion, I didn't think about that.

---------- Post added at 19:11 ---------- Previous post was at 19:08 ----------

kenleigh, I advise you to find a nice book or online manual and refer to it when you have complications with syntax.
Personally, I sometimes use this
 
Alexium said:
Interesting conclusion, I didn't think about that.

---------- Post added at 19:11 ---------- Previous post was at 19:08 ----------

kenleigh, I advise you to find a nice book or online manual and refer to it when you have complications with syntax.
Personally, I sometimes use this
Click to expand...

Thanks for the link Alexium and for the expert tips FvM.
From the point of view of the bidirectional pin question, what should I do now? I mean is something like
"inout sda" the way to go?
and then how do I assign sda inside procedural blocks, since the compiler doesn't allow net data types to be assigned inside proc blocks.
 

kenleigh said:
is something like
"inout sda" the way to go?
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Indeed it is.
You then declare a reg signal, say sda_out, in your module. You work with this reg in a procedural block. And somewhere in the module outside of the procedural block you write a statement:
Code: 
assign sda = (write_enable == 1'b1)? sda_out : 1'bz

where sda is the bidirectional net port.
 
Alexium said:
Indeed it is.
You then declare a reg signal, say sda_out, in your module. You work with this reg in a procedural block. And somewhere in the module outside of the procedural block you write a statement:
Code: 
assign sda = (write_enable == 1'b1)? sda_out : 1'bz

where sda is the bidirectional net port.
Click to expand...

Many thanks, will try this one out and keep you posted!!

---------- Post added at 19:20 ---------- Previous post was at 19:18 ----------

the write_enable is of datatype reg, right? and I have to manually set or reset this bit when I am doing reads or writes, right?
 
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kenleigh said:
Many thanks, will try this one out and keep you posted!!
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Your welcome, hoping I helped.

kenleigh said:
I have to manually set or reset this bit when I am doing reads or writes, right?
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Exactly!

kenleigh said:
the write_enable is of datatype reg, right? and
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That's your decision. It need not to be reg. I was thinking of making write_enable an input port of the receiver module, of type wire. But yes, eventually this port will receive it's value from a reg.
 

Alexium said:
I was thinking of making write_enable an input port of the receiver module, of type wire. But yes, eventually this port will receive it's value from a reg.
Click to expand...

In fact the 'sda' pin is acting as a transmit sometimes and a receive sometimes, at the moment I'm trying to implement an I2C master, not quite sure what you mean by "receiver module"?
 

If I had to make an I2C module, I would split it into two: receiver and transmitter. If you're not planning to do such a thing - never mind, It seems to me you get my point.
A year ago I've made a PS/2 controller module. PS/2 is also a serial port with one bidirectional data line, so I'm merely telling you how I made that controller. I'm not forcing you to adopt my design decisions, it would be better if you come your own way to understanding the problem :)
 
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