28x1 to 28x2

[thunderace7]

Hi. I've a project using a 28x1 chip but I need another output pin and the 28x2 seems to use the serial out as an optional output. Can I use the 28x2 as a direct plug-in replacement for my 28x1 as it seems to be pin-compatible. I am using an external 4Mhz resonator for the x1 so I guess I must change the Pause commands accordingly as the x2 runs faster. I think I must also change pins commands to pinsb and set the direction of the A and B ports. Is there anything else I've missed?

Thanks.

 

[westaust55]

Yes, the 28X2 is a direct drop in from a physical perspective.

As well as the consideration for clock frequency. You need to specifically set portB pins as outputs and if using ADC then you should specifically setup those pins as well

 

[inglewoodpete]

I am using an external 4Mhz resonator for the x1 so I guess I must change the Pause commands accordingly as the x2 runs faster.

It's best not to guess. Read the manual on each time-related command.

In the case of the pause command, the default speed of the 28x2 is twice that of the 28x1. Rev-Ed have compensated for this in the firmware. So Pause 10 will give a 10mS delay in both chips when they run at their respective default speeds.

 

[hippy]

There's also the X2 Conversion Wizard of the Programming Editor.

 

[thunderace7]

Thanks to all who replied. I didn't even know that there was an x2 conversion wizard (or any other wizards). I'll take a look at them and see what they do.

 

[John West]

I know about the wizards, yet forget to use them on a regular basis. I get immersed in the problem at hand and fail to recall that Rev. Ed. has taken a great deal of time and effort to make my coding easier.

I'm simply not accustomed to having so much support for my coding. (I'm used to, in the past, spending days staring at FOR/NEXT loops that won't run because they have the letter "oh" where they should have a zero.)

But sooner or later, in desperation, I look around the PICAXE editor, and low and behold, there's the solution to my problem, just a click of the mouse away.

Now, if I could just remember it sooner.....