Internal clock speed vs temperature
BradC
Posts: 2,601
This has been driving me batty and I figured I should not be the only one to get a laugh out of it.
I've just spent 4 hours trying to figure out what I've done to break what was perfectly operational propeller loader code operating at 230400 Baud.. It works solidly at 115200 baud, but it was just flaking out randomly at the higher baud rate.
It was working perfectly yesterday and now it's just plain unreliable..
In a lightbulb moment (4 hours in mind you) I hit the chip with a can of freezer spray and *whamo* it was reliable again.
The long and the short of it is once the propeller chip reaches about 40 Deg C, the internal clock slows enough that it can't keep up with a bitstream that fast!
Yesterday my ambient room temperature was 25C. Today it's 34C.
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Cardinal Fang! Fetch the comfy chair.
I've just spent 4 hours trying to figure out what I've done to break what was perfectly operational propeller loader code operating at 230400 Baud.. It works solidly at 115200 baud, but it was just flaking out randomly at the higher baud rate.
It was working perfectly yesterday and now it's just plain unreliable..
In a lightbulb moment (4 hours in mind you) I hit the chip with a can of freezer spray and *whamo* it was reliable again.
The long and the short of it is once the propeller chip reaches about 40 Deg C, the internal clock slows enough that it can't keep up with a bitstream that fast!
Yesterday my ambient room temperature was 25C. Today it's 34C.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Cardinal Fang! Fetch the comfy chair.
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· -- Carl, nn5i@arrl.net