Newbie Questions for the BX-35

Started by Rich Mays March 6, 2007
I am considering using a BX-35 for a project and I have a few questions.

First, from posts in this newgroups, it looks like to use more than 2
UART's you simply share COM3 between the second and subsequent UART's
calling DEFINE COM3 and OPEN COM each time you want to switch between
them. Does this significantly slow down the processor? Do you know
how big a performance hit this incurs? If this does make for
performance issues, are there any alternatives to this?

Second, I have read some posts about overclocking the BX-35 to get its
performance up to the BX-24p's level. The post I read said that 10Mhz
works fairly reliably. Do you have any experience with this? Is there
a particular crystal that you would recommend? Would the values of the
22pF capacitors need to be changed when using a different crystal?

Third, I saw another post that talked about using a 64K EEPROM for
extra code space with the BX-35. Do you have a specific 64K EEPROM
that you would recommend for this? The post talked about letting the
BASICX IDE know about using the 64K EEPROM. Is the entire 64K
available for use by BASICX code?

Is there any 'unofficial' documentation that covers any of these topics?

I would greatly appreciate any help you can give on these questions.

Thanks,
Rich
Rich,

One thing that has been mentioned with respect to changing the clock
frequency is that the serial baud rates will change as well. Unless
you can set the counters or establish a relationship with the clock
frequency that shifts one baud rate up to another (say 14400 for 9600)
there will be problems with serial I/O.

Other timer-based commands will change as well.

If the standard clock frequency doesn't do it for this otherwise very
capable chip, there are other products that run faster.

Good luck,

Dennis
--- In b..., "Rich Mays" wrote:
.....

> Second, I have read some posts about overclocking the BX-35 to get its
> performance up to the BX-24p's level. The post I read said that 10Mhz
> works fairly reliably. Do you have any experience with this? Is there
> a particular crystal that you would recommend? Would the values of the
> 22pF capacitors need to be changed when using a different crystal?
>