I am using the internal oscillator (FOSC = 7.37 Mhz) of the dsPIC33EV256GM102. I have a 1602 LCD connected to the PIC via 4 data, and enable, RW, and RS control lines.
I write initialization commands to the LCD and then two lines of text. That works fine.
After 2 minutes and 10 seconds the enable line quickly pulses high-low causing something to be written to the LCD. It happens again in another 2:10 and then again, repeatably.
All my program does right now is initialize the LCD, write two lines of text and go directly into a while(1).
I have tried setting the LCD enable low on every iteration of the While. I have tried latching the enable low before going into the While. I have moved the enable to another pin but the pulse still occurs on that pin. If I remove the enable line after writing the data, the problem goes away.
Any thoughts what might cause this kind of behavior or what additional troubleshooting steps I might take?
I am using pin 24 labeled RPI45/PWM1L2/CTPLS/RB13 for the enable but I have also tried pin 23 labeled RPI44/PWM1H2/RB12. I am not executing any code related to peripheral pin select yet.
When I download the program via the Pickit3, for the first POR while the Pickit3 is still in the circuit, there is some spurious text written to the LCD. So I have to disconnect the Pickkit3 and do another POR before the two line of text are written correctly without any unwanted additional data writes.
In conclusion there are two issues really or perhaps they are related?
Related
I'm using the builtin FIFO, in FWFT mode. I try resetting it for 9 clocks, then leave the reset line low at the beginning. There is a large gap before the first write enable rises.
Modelsim then complains that I have not reset the FIFO correctly when the write enable goes high. Yet I see the correct data coming in and out of the block. If I don't reset it, or I don't leave a gap between the reset and the first write enable, then I don't get correct data out. Why is this happening?
My only hunch is that I'm compiling and running modelsim using the -nodebug flag on the IP cores, but I can't remove it at the moment to test out my theory.
I have a a Sparkfun Max 7456 breakout board that I am trying to rewrite the character table to an ASCII format. I have been following the Arduino + MAX7456 OSD thread but cannot seem to load the .mcm file to the breakout board. I have tried hyper terminal and tera term. Tera term allows me to "transfer" the mcm file but I do not get any type of confirmation in the terminal window. When I try simple sample code like "Hello World.ino" I get no response and the default character set is still displayed. Hyper terminal tells me there is a COM port conflict with the Arduino IDE. I know the steps are available in the above mentioned thread but the picture/ code resources have mostly been removed. I don't know if I'm missing something in the code or if I am not using the terminal program correctly. I have the following connections between the breakout board and the Uno and have been trying Arduino code provided at the start of the thread;
Breakout/ Uno;
CS-->D10
SDIN--> D11
SCK--> D12
SDOUT--> D13
+5V
GND
I have tried using wires that are <5cm and >=10cm and I am using NTSC. Can anybody determine what I am doing wrong or point me in the right direction please. Thanks in advance,
I figured out my issue. Using Google translate I was able to get code from;
http://f5mna.free.fr/Arduiexpert.htm
Previously, I was only making the connections listed in the code when the full list is;
D13--> SCLK
D12--> SDOUT
D11--> SDIN
D10--> CS
+5VDC must be applied to the +5V pin on the board as well as a 1k resistor in series with LOS and a 10k with RESET.
As for using tera term. First shutdown the Arduino IDE and open the connection in the terminal program. The code provided in the above link will indicate it is ready for file transfer and will prompt you with a transfer complete message.
All in all, simple solutions but I was a newcomer to a very old thread. Hope this helps anyone else having the same issues in the future.
I am trying to use the expansion header to control a couple motors and auxiliary task mechanism. For this I am using the appropriate pins as GPIO and merely attempting to send high or low signals as needed by the robot. (For instance, I might need the robot to move forward and so I'd send high signals on both sets of pins, whereas if I needed the robot to turn I'd send a high signal to one pin and a low to the other.)
However, the problem is that the pins will only stay high! I've followed the conventions for sysfs just via the terminal, and, although I'm able to set the "values", "active_lows", etc. to 0 or 1, I can't actually get the pins to send 0V. After checking the beagle.h file I used for u-boot it looks like the multiplexer mode is configured correctly. This is also reflected when I get the info from sys/class/gpio/gpio%/% and sys/kernel/debug/gpio. Furthermore I don't get any errors or indication from anywhere that there is something wrong...it just doesn't work!
What should I do? For the first time in my life I have seemingly exhausted the internet...
details:
Beagleboard xm rev c1
ubuntu 12.04
kernel 3.6.8-x4
Im pretty new to the beagle board and I have recently been trying to configure the GPIO pins on my classic beagleboard c4, which i believe should be fairly similar.
Half of my GPIO pins seemed to work fine and the other half seemed to remain high or low no matter what i did. Even though they were configured the same way as the working pins in /sys/class/gpio/
have you tried to use other gpio pins?
I ended up following http://labs.isee.biz/index.php/Mux_instructions
to configure the mux to 4 and now i can control the pins that were not working.
I basically used the command:
sudo echo 0x004 > /sys/kernel/debug/omap_mux/(mux 0 name)
where (mux 0 name) was the name of the subsystem for the mux 0 setting for the gpio pin you wish to configure
ie. for gpio 183 on beagleboard c4
sudo echo 0x004 > /sys/kernel/debug/omap_mux/i2c2_sda
Though I had to change permissions to modify these files
As I said I am pretty new to the beagleboard and ubuntu but this worked for me so I thought I would share it with you, I hope it is of some help.
Regards;
Paul;
It seems that the beagleboard expansion pins are numbered in alternating fashion, as clearly and professionally depicted here.
Thanks to everyone for your help. I now know way more than I should about GPIO on OMAP systems (and so do you). Good luck on finals/life!**
tl;dr I'm an idiot!
I am having an odd problem with my PIC16F88. I have an EEPROM connected thru I2C and it works flawlessly until I write to portb.bit6. From that point on, I start getting garbage from my EEPROM. I tried explicitly disabling Timer 1, which uses portb.6 for oscillator-out but that did not help. I tried cutting the trace from the PIC pin (pin 12) so that there is nothing physically connected to it and that did not help. My C code is simple, either portb.6 = 0 or portb.6 = 1. Either way, reading the EEPROM thru I2C fails forever more. The generated ASM code looks fine. The problem occurs on every board that I have tried it on, so it is not localized to one PCB. I am mystified. Any suggestions?
It turns out that it is necessary to write a zero bit to the SCL and SDA pins every time before writing to any bit in portb. FWIW, I was bit-banging rather than using the SSP peripheral of the PIC16F88 for the I2C communicaitons. Thanks to the people on the Yahoo group, Electronics_101, for figuring out this puzzle.
I can properly read/write to a 2GB Kingston Micro SD using single pin SPI, but after writing using the WRITE_MULTIPLE_BLOCK command to write several blocks, the card goes into idle mode. I know this because when I try send a command to write more data, the card returns an 'in idle state' flag. I created a work around that pulls the card from idle after each write but this severely reduces the bandwidth. Does anyone know why this happens?
Also, the maximum SPI Baud I have obtained is 1Mbs. When I set the SPI clk to >1MHz the commands do not work properly. If I send commands at a baud of < 1Mbs then send the data at >1Mbs, the data is corrupted. Is there a reason I have not been able to get the 25MHz specification speed as listed in the SDCARD.org spec on p2?
https://www.sdcard.org/developers/tech/sdio/sdio_spec/Simplified_SDIO_Card_Spec.pdf
I got SPI Speeds less than 1 MBit/s when I tried to use the wrong SPI clock polarity once. Double check this, and this is also a possible candidate as a source for you "idle" error.