Software > Software
8 characters in the path or file name ? and starting AXON not on USB...
Lester:
All grounds are connected by pluggin leads and are pretty solid.
Grounds for the LCD are on the 5V regulated strip
Grounds for the GPS are on the 5V regulated strip
Grounds for the DroneCell are on the 6V (battery) strip
Yes the code is using the USB UART.
I'm beginning to suspect the capacitor charging time constant but does that explain the blinking cursor? I need to figure out how to set the default for that.
Admin:
--- Quote from: Lester on June 16, 2012, 04:13:13 PM ---I am using the 4 UARTs.
1 for the USB connection
1 for a GPS module
1 for a DroneCell modem
1 for future expansion to OBD II data.
--- End quote ---
Is the LCD also using an UART?
--- Quote ---If I unplug the USB, after checking just now and playing some more is I get weird characters on the LCD
--- End quote ---
You mean after you turn everything on, then you remove the USB, right? And then the only error you get is weird characters?
But if you never had USB in at all, nothing happens? ie no LEDs turn on, etc?
Are you using the SPI pins, or I2C?
Lester:
LCD is not using a UART. 4 line connection, no serial LCD.
Maybe I misspoke. If I unplug the Axon after starting connected to the PC USB with power on the PC everything works fine, no problems.
It's only when I start/power up by the switch with USB unplugged and only getting power from the wall transformer that I get strange LCD behavior and on a rare occasion nothing comes up on the LCD although something is happening as LED blinks. I am getting more and more convinced this is a problem caused by charging the big cap. Is that possible? Maybe I should just sit idle for a bit longer at init.
A quick check of time constant on the cap.... at a 1K load that 3300uF cap has a time constant of 3.3 seconds, scales proportionate to that for higher loads. 2K is 6.6 vseconds and so on. And, that's just to get to 63% charge. Tomorrow I will try to get a trace on the scope to see what the voltage is doing, should have done that first I guess.
Does the USB connection actually keep the capacitor charged?
SPI is setup in the project from Project Designer (Webbotlib) but not yet implemented for an SD card, so no connections to those pins yet.
Admin:
What is your current draw? Yea, definitely see what the voltage is doing. Your wall wart could be acting funny.
--- Quote ---It's only when I start/power up by the switch with USB unplugged and only getting power from the wall transformer that I get strange LCD behavior and on a rare occasion nothing comes up on the LCD although something is happening as LED blinks.
--- End quote ---
Ok, so everything else works fine, but just the LCD acts strange?
Do you have the LED blinking in your code? A blinking LED could mean your mcu is resetting.
--- Quote ---SPI is setup in the project from Project Designer (Webbotlib) but not yet implemented for an SD card, so no connections to those pins yet.
--- End quote ---
Disable the SPI in PD and see if that has any effect.
Lester:
I'm not using a debug adapter so I can't see what registers or ports are doing but....
infrequently but it has happened..... yes the LED blinks but not like it's resetting in fact it's very rythmic 8 flashes and a pause, 8 flashes and a pause, and so on that may have originated by a reset, but the flashing doesn't occur every power up. I suspect there is a timing issue with the DroneCell also doing an init and not related to anything else.
The real manifistation of odd behavior is what the LCD does during power up (with or without the USB plugged in) and ultimately do I have a blinking cursor or no blinking cursor. I don't mind the blinking cursor, but would prefer to be able to turn it on or off with software, not left to chance. So, before I go on with this I need to resolve this LCD issue.
I'll check voltage across the cap tomorrow and try to get a current reading.
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