See Also

Programming the RB Series Response Pads for a programming example written in C

The RB Series Response Pad Protocol
Last Revision: July 25, 2002

The information in this article applies to:

Anyone who wants to understand the protocol used by the RB Series response pads to transmit their information to the host computer.

Summary

The RB Series response pads protocol is a simple yet efficient method of transmitting information to the host. It is directly supported by SuperLab and other programs. It is also emulated on the Lumina MRI response pads and other devices.

Technical Details

The 4 MHz microcontroller inside the response pads keeps an eye on the the status of the keys and sends one byte to the host every time a key is pressed or released. In other words, when a key is pressed, a byte is sent. When the key is released, another byte is sent. Each bit within the byte corresponds to a key.

The built-in microcontroller takes care of debouncing the keys if necessary. This guarantees that, when a key is pressed, one and only one byte is sent to the host instead of a stream.

The byte sent from the RB-400, RB-410, and RB-420 models has the following format:

Bit	RB-4x0 Function
0	Always set
1	Always set
2	Cleared when leftmost button is pressed (normally set)
3	Cleared when second button from the left is pressed
4	Cleared when third button from the left is pressed
5	Cleared when rightmost button is pressed
6	Always cleared
7	Always cleared

The byte sent from the RB-600, RB-610, and RB-620 models has the following format:

Bit	RB-6x0 Function
0	Cleared when leftmost button is pressed (normally set)
1	Cleared when rightmost button is pressed
2	Cleared when second button from the left is pressed
3	Cleared when third button from the left is pressed
4	Cleared when fourth button from the left is pressed
5	Cleared when fifth button from the left is pressed
6	Always cleared
7	Always cleared

The byte sent from the RB-520 model has the following format:

Bit	RB-520 Function
0	Always set
1	Cleared when the top button is pressed
2	Cleared when the left button is pressed
3	Cleared when the center button is pressed
4	Cleared when the right button is pressed
5	Cleared when the bottom button is pressed
6	Always set
7	Always set

The byte sent from the RB-820 model has the following format:

Bit	RB-820 Function
0	Cleared when rightmost button is pressed OK
1	Cleared when third button from the left is pressed OK
2	Cleared when second button from the left is pressed OK
3
4	Cleared when fourth button from the left is pressed
5	Cleared when fifth button from the left is pressed
6
7	Cleared when leftmost button is pressed OK

The RB Series Response Pad Protocol Last Revision: July 25, 2002

The RB Series Response Pad Protocol
Last Revision: July 25, 2002