Bit bashed RS232 with 32.768 kHz crystal, Will with work?

[William At MyBlueRoom]

Bit bashed RS232 with 32.768 kHz crystal, Will with work?

Thinking of using a 12C508.

 

[Nigel Goodwin]

Re: Bit bashed RS232 with 32.768 kHz crystal, Will with work

Bit bashed RS232 with 32.768 kHz crystal, Will with work?

Thinking of using a 12C508.

Yes, of course it will work! - depending what speed you're wanting!.

But why not use a 12F series chip, rather than the OTP 12C series?.

 

[William At MyBlueRoom]

At what baud though?

I've 9600 at 4 MHz but what can I expect from 32 kHz? Half duplex is fine.

 

[Nigel Goodwin]

Re: At what baud though?

I've 9600 at 4 MHz but what can I expect from 32 kHz? Half duplex is fine.

Work out the instruction timing required, if I remember correctly one bit at 9600 baud is 104uS?.

 

[evandude]

I don't think it's very feasible... first off, one instruction cycle at that frequency is about 122us... even at as low as 300 baud that's only about 27.3 cycles per bit... but more importantly, it's not a nice round multiple, which means that the bit durations are going to be a bit off, which will probably mean the serial data will be too messed up to read on a computer or other device.

 

[atferrari]

Timing

Yes, 104 us.