rs232 communication speeds over Embedded linux ARM

gigin

Hi ,

I am using ARM embedded linux 2.6.30 on a samsung s3c2440. When I try to transfer bulk data (eg. a database) over serial port, I am getting speed of around 2-3 kbps. I am using a rs232 interface from my PC to the ARM development kit. The same code on PC to PC transfer gives me speed of 20kbps.

Is that the best speed I can get on an embedded platform. Can I do any to improve the performance, like mapping DMA channel for a UART or increasing the fifo size etc. etc.

Please help.

Thanks

woboyle

What baud-rate and flow control are you using for the port? I have an ARM board w/ multiple rs-232 ports and can get 115kbps out of them.

gigin

Hi,

I use a baudrate of 115200 and flow control is none.

Once I changed the fifosize of the serial port from inside the driver, I was able to increase the speed a little bit (to 4kbps), but not considerably.

woboyle, are you able to do the data transfer at a rate of 115kbps. If so, is your serial port using a DMA to transfer data. ? what is the value for fifosize ?

Thanks
gigin

woboyle

The most important thing is to utilize hardware flow-control at those speeds, otherwise no matter how big, the fifo buffer overflows. I don't pay attention to the DMA transfer issue - the boards I use run a version of Debian Etch and the serial drivers are built into the kernel. I haven't futzed with their configuration - only file system support and such.

chekkizhar

PC to PC transfer will be faster than PC to Embedded devices, due its Processor speed and a good enhanced OS will be in PC.

ARM kit is a Embedded device, so, the speed will be obviously less than PC-PC communication. In you case PC to PC also slow, a dead slow.

Check your settings in PC side too.
Try to transfer files from 512kb then increase step by step and find out where the things are going wrong.

Goineasy9

Six months later ... is the OP still around?