| ??? 02/06/07 19:20 Read: times |
#132157 - I'm not sure that's the issue Responding to: ???'s previous message |
I think my ISR is fast enough. I thought about the latency issue, but I did two things to disprove this in my mind. First, I lowered the baud rate to 19kbps and it still had the same issues though with less frequency than the higher baud rate. Second, I did some algebra. 10 bit uart @ 115.2kbps = ~87 uS per uart transmission. My micro clock speed is 24 MHz. In 87 uS that means I get about 2000 system clocks. If I over estimate and make the math easy and say that an average instruction takes 5 clocks, that means I can have about 400 instructions take place during a uart transmission. As it is, the longest possible path in my ISR is on the order of 20 instructions. I should, therefore, be well under the latency requirement. When I get home I'll look more closely with the scope at the output of realterm, but I'm pretty sure that the issue is on the terminal side. I'll be able to further prove this when I get a piece of hardware that streams 115.2kbps in a few weeks. I'll keep the forum updated....
D |
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report | 01/01/70 00:00 | |
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| thank you | 01/01/70 00:00 | |
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