Hey guys, I'm pretty new to this whole hacking scene, so I've got a [hopefully] basic question. I put my RPi 16x2 LCD + Keypadhttp://www.adafruit.com/products/1110 kit together, followed all the steps http://learn.adafruit.com/adafruit-16x2 ... y-pi/usage, and got nothing on the display. I checked all the solders for shorts, and a few of them displayed inter-connectedness, but I'm assuming that's normal as they're connected by the board. I started backtracking and tried the I2C Detect command, and got this:
>>pi@raspberrypi ~/Adafruit-Raspberry-Pi-Python-Code/Adafruit_CharLCDPlate $ sudo i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
10: 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
20: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
30: 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
40: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
50: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
60: 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
70: 70 71 72 73 74 75 76 77
Now on the tutorial it says you're just supposed to get one response, in 0x20, but I got a response from literally every position. Is this the problem, or is there something else I'm probably doing wrong? I followed all the other directions, and investigated more deeply, but this is the only thing that struck me as odd.
Thanks,
sprombo
I2C Problem with RPi 16x2 LCD + Keypad
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- adafruit_support_bill
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Re: I2C Problem with RPi 16x2 LCD + Keypad
That does look pretty strange. If you disconnect the LCD/Keypad, do you still get the same response from i2cdetect?
If you post photos of the front and back of your board, we'll check it over too.
If you post photos of the front and back of your board, we'll check it over too.
- adafruit_support_mike
- Posts: 67454
- Joined: Thu Feb 11, 2010 2:51 pm
Re: I2C Problem with RPi 16x2 LCD + Keypad
FWIW, you'd get those results from an SDA line that's shorted LOW.
An I2C bus master detects other devices by sending a control byte that contains the device address during the first 8 ticks of SCK, then looking for an ACK. Slave devices generate an ACK by pulling SDA LOW on SCK's 9th tick.
An I2C bus master detects other devices by sending a control byte that contains the device address during the first 8 ticks of SCK, then looking for an ACK. Slave devices generate an ACK by pulling SDA LOW on SCK's 9th tick.
Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/