Models 707B and 708B Switching Matrix Reference Manual
Section 4: Theory of operation
707B-901-01 Rev. B / January 2015
4-7
Row and column labels
The row and column labels are updated by writing to the devices serially. They handle their own
brightness and refresh controls, alleviating the main microcontroller from performing these tasks. As a
result, these are only updated when the data changes and a command from the instrument is issued
to update the label.
12 x 12 LED matrix
The 12 x 12 matrix array of LEDs is driven by PWM signals that cause the intensity of the LED to be
bright or dim based on the appropriate setting from the instrument.
Each row and column is updated sequentially. The entire display has a refresh rate of approximately
60 Hz. The time domain details of display refreshing are shown below.
Figure 81: Model 707B display refresh
Slot indicators
The slot LEDs are treated the same as the matrix LEDs, as additional 13th and 14th columns.