Hi all,

I am having problems using the Hitachi SH7043 for RS232 communication
beyond 38400 Kbps. ( I keep getting Overrun Errors).

I suspect that the UART's reliable communication limit is 38400Kbps

Any help would be greatly appreciated.

Thanks in advance,
Vivek

"vivek" <vivek.seetharaman@wipro.com> wrote in message
news:1128504668.499362.97170@g14g2000cwa.googlegro ups.com...
interrupts. If you are using polling to check for characters received you
need to be sure that your code checks back before the next character is
received.

Stan

Thanks so much for your prompt reply, Stan.
I'm using interrupts as well. I am able to send data at 115Kbps
successfilly but
reception of chunks of data(say 1k) eventually results in an Overrun
error.

buffer. I was under the impression that because the SCI does not have a
FIFO queue for buffering, high baud rates would be unreliable.

But the fact that you are able to communicate at 115Kbps suggests that
my understanding is incorrect. I will go back and try to figure this
out.

I would greatly appreciate any advice that you can offer.

Thanks again !
Vivek

vivek wrote:

Even when interrupts are used, there are some possible traps:
* Are there any other, higher-priority interrupts that run for a
significant amount of time?
* Are there lower-priority interrupts that "forget" to re-enable
interrupts at the beginning of the interrupt routine?
* Are there critical sections in the code that turn off interrupts?

Any of these can cause interrupt handling to be delayed long enough for
characters to be missed.

Anyway, there is a solution. Like many other Renesas chips, the 7043
contains a DTC (Data Transfer Controller). The DTC can push data in the
background, without generating an interrupt.You can, for example,
program the DTC to push serial data into a ring buffer, which you poll
periodically.

Thanks Hans! Appreciate the help.