I2C - Keypad Issues
Posted: Fri Jan 05, 2007 2:16 pm
Hello,
I am struggling with the keypad feature using I2C. I am using a GLK24065-25 Rev 2.0.
First, I notice that when using the poll key press the return bytes don't conform to the standard listed in the manual. According to the manual the return bytes are supposed to have the MSb set if there are more key presses to come. I have found this not to be the case. The MSb is never set. In order to read all key presses I have to continue the read cycle until I get 0x00. This is a minor issue but I just want to verify that this is the case.
Second, I am having difficulties with duplicate key presses. For example, if I press the #1 and the #4 keys I get the same return value. This happens for a total of 4 keys (4 keys have pairs). So I have 17 working keys out of 25. I have verified the hardware (wiring of the keypad). It is correct. I can reproduce the issue by shorting the pins directly on the LCD... so I have eliminated everything external to the LCD. Is there perhaps a known issue with this?
Thanks in advance!
I am struggling with the keypad feature using I2C. I am using a GLK24065-25 Rev 2.0.
First, I notice that when using the poll key press the return bytes don't conform to the standard listed in the manual. According to the manual the return bytes are supposed to have the MSb set if there are more key presses to come. I have found this not to be the case. The MSb is never set. In order to read all key presses I have to continue the read cycle until I get 0x00. This is a minor issue but I just want to verify that this is the case.
Second, I am having difficulties with duplicate key presses. For example, if I press the #1 and the #4 keys I get the same return value. This happens for a total of 4 keys (4 keys have pairs). So I have 17 working keys out of 25. I have verified the hardware (wiring of the keypad). It is correct. I can reproduce the issue by shorting the pins directly on the LCD... so I have eliminated everything external to the LCD. Is there perhaps a known issue with this?
Thanks in advance!