Matrix Orbital LK202-25 Legacy User Manual

Page 25

4.5.1 Auto repeat mode on (254 126 [mode]) (R)

[mode] = 0x00 gives Resend Key Code mode
[mode] = 0x01 gives Key Down / Key Up code mode
Two Modes of auto repeat are available and are set via the same command.

Resend Key Code: This mode is similar to the action of a keyboard on a PC. In this mode, when a

key is held down, the key code is transmitted immediately followed by a 1/2 second delay. After this

delay, key codes will be sent via the RS-232 interface at a rate of about 5 codes per second. This mode

has no effect if polling or if using the I

C interface.

Key Down / Key Up codes: This mode may be used when the typematic parameters of the “Resend

key code” mode are unacceptable or if the unit is being operated in polled mode. The host system

detects the press of a key and simulates an auto repeat inside the host system until the key release is

detected. In this mode, when a key is held down, the key code is transmitted immediately and no other

codes will be sent until the key is released. On the release of the key, the key release code transmitted

will be a value equal to the key down code plus 20 hex. For example, when the key code associated

with key ’P’ (0x50) is pressed, the release code is ’p’ (0x70). In RS-232 polled mode or via the I

interface, the “Key down / key up” codes are used; however, the user should be careful of timing

details. If the poll rate is slower than the simulated auto-repeat it is possible that polling for a key up

code will be delayed long enough for an unwanted key repeat to be generated.

chapter

Figure 22: Poll Timing

4.5.2 Auto repeat mode off (254 96) (R)

This command turns off auto repeat mode.

4.5.3 Auto transmit keypresses on (254 65) (R)

In this mode, all keypresses are sent immediately to the host system without the use of the poll keypad

command. This is the default mode on power up.

Matrix Orbital

LK202-25