??? 02/28/05 02:39 Read: times |
#88596 - connecting a keypad Responding to: ???'s previous message |
Yogesh:
Here is the basic scheme to attach a keypad to a microcontroller. This example shows a 16 key matrix organized as 4 rows by 4 columns. The example shows port 1 being used. As shown the software would scan the rows as outputs, one at a time being low and then monitor on the column pins as inputs. The resistors keep the column pins high when there is no low from a row output via a closed switch. ![]() You could look at the various software source codes on this web site for a sample of how to implement a keypad scanning algorithm. Here is a link to some C code I posted a while back. Note that in that example the "rows" and "columns" are interchanged with regard to which set of 4 pins are the outputs and which 4 are used to monitor as inputs. Karas's Keypad Scanner Code In C Michael Karas |
Topic | Author | Date |
Connecting LCD and Keypad to 8051 | 01/01/70 00:00 | |
No problem | 01/01/70 00:00 | |
Beats me. | 01/01/70 00:00 | |
74C992 | 01/01/70 00:00 | |
Will the real encoder please stand up... | 01/01/70 00:00 | |
Part Cost | 01/01/70 00:00 | |
Or One Part..... | 01/01/70 00:00 | |
Connecting LCD & Keyboard | 01/01/70 00:00 | |
connecting a keypad | 01/01/70 00:00 | |
selling antiques as new![]() | 01/01/70 00:00 |