Soft Uart receives only 25bytes

binu_ji · Joined: 07 Jan 2006 Posts: 17

Hi
I am using 2 soft usart, in which 1 is connected to a GPS and other to GSM modem.

The GPS usart can works well, it can receive all the data correctly.

While the GSM usart receives only 25bytes correctly and the remaining are junk values.

can anybody help me over this.

Binu

Evert :-) · Joined: 18 Feb 2005 Posts: 2156

What avr, clock source and Bascom version are you using?

binu_ji · Joined: 07 Jan 2006 Posts: 17

Thanks for your quick reply evert

I am using Atmega8 and 3.68mhz crystal
My bascom V1.11.9.0

AdrianJ · Joined: 16 Jan 2006 Posts: 2483 Location: Queensland

IMHO software UARTs are or debugging, or very non-critical applications only.

You cannot ( in general ) run two software UARTS for receive at the same time. SOFTWARE UART means exactly that, that the UART receive is using software to do the bit collecting. While its doing that on one channel, it must ignore the other one. Only if the messages on each channel are at different times, and never overlap, will you ever get this to work. My recommendation is you use at least one hardware UART, if not two. That is what Atmel provide them for.

Even with one ( or two ) hardware UARTS doing the receiving, you still need to run with input buffers, so that the actual inputs are done by interrupts. Bascom provides these, and the ischarwaiting and inkey commands to decide when to get a character.