| ??? 12/30/04 22:31 Read: times |
#84151 - Oh yes it is! Responding to: ???'s previous message |
Jez Smith said: (my emphasis)
The standard 8052 hardware uart oversamples the serial bit stream input by 16 times the baud rate,which makes software uart with the same performance an even more onerous task. Jan Waclawek said:
But in this case, you don't need to interrupt in this high rate all the time, only while searching for the beginning of the start bit, then you interrupt at the bit rate But, as Jez said, this does not give the same performance as a hardware UART: in particular, this means that you are susceptible to noise and glitches in the data that would be "filtered-out" by the hardware UART's 16x sample rate. Note that the hardware UART uses a "majority vote" of 3 (I think) samples - and will abort the character if it can't find a steady state in a bit position. Full details in the "bible." Of course, doing a software async transmitter is a lot easier than doing a software async receiver! |
| Topic | Author | Date |
| Polling/Interrupt For Serial Input | 01/01/70 00:00 | |
| bible time | 01/01/70 00:00 | |
| Soft UART | 01/01/70 00:00 | |
| Hardware? | 01/01/70 00:00 | |
| SW UART is not a taboo! | 01/01/70 00:00 | |
| yes... | 01/01/70 00:00 | |
| think before you do | 01/01/70 00:00 | |
| Use oversampling | 01/01/70 00:00 | |
| soft UART | 01/01/70 00:00 | |
| Half bits | 01/01/70 00:00 | |
| Oversampling | 01/01/70 00:00 | |
| It's not so bad | 01/01/70 00:00 | |
| Oh yes it is! | 01/01/70 00:00 | |
| Haven't read it completely? | 01/01/70 00:00 | |
| neither have I | 01/01/70 00:00 | |
| Sure you did not! | 01/01/70 00:00 | |
| did I miss it | 01/01/70 00:00 | |
| Problem displaying posts? | 01/01/70 00:00 | |
| sure that will work | 01/01/70 00:00 | |
| NOT A PIC | 01/01/70 00:00 | |
| Just forget 89c51 then. | 01/01/70 00:00 | |
| @Erik | 01/01/70 00:00 | |
| ...all said already. | 01/01/70 00:00 | |
| OS? Threads?! | 01/01/70 00:00 | |
| Appnote to read | 01/01/70 00:00 | |
| threads | 01/01/70 00:00 | |
Problem Solved | 01/01/70 00:00 |