10.1.1 I2C Interface
The keypad is read by I2C master read. In short, this means that a read of the module will always return
the ?rst unread key press. A read is initiated by writing to th
e module with its base address plus 1, then
clocking the module's return byte after the module releases
the SDA line. Much more detail on this basic
I2C function can be found in the I2C speci?cation by Phillips.
10.1.2 RS232 Interface
By default on any press of a key, the module will immediately send out the key code at the selected baud
rate. This behavior can be modi?ed using commands found in th
e next section.
10.2 Auto Transmit Key Presses On
Syntax
Hexadecimal 0xFE 0x41
Decimal 254 65
ASCII 254 “A”
Description In this mode, all key presses are sent immediately to the host system
without the use of the poll keypad command. This is the default mode
on power up.
NOTE
This command is not available in I2C.
Remembered Yes
Default On
10.3 Auto Transmit Key Presses Off
Syntax
Hexadecimal 0xFE 0x4F
Decimal 254 79
ASCII 254 “O”
Description In this mode, up to 10 key presses are buffered until the unit is polled by
the host system, via the poll keypad command 254 38. Issuing this
command places the unit in polled mode.
NOTE
This command is not available in I2C.
Remembered Yes
Matrix Orbital GLK12232-25-SM
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