Setting up your System
© Copyright ARM Limited 1999. All rights reserved.
2-3
2.1.1
Setting the bus clock frequency
The ARM710T header card requires the bus clock frequency, BCLK, of the board to
be set to 4, 8, 16 or 20MHz. This is set by changing the FREQ SELECT switch, S1, on
the ARM development board, shown in Figure 2-2.
Figure 2-2 Position of switch S1
Table 2-1 shows the switch settings for the allowable bus clock frequencies.
Note
Do not select any combination other than shown in the table.
ARM development board
ARM740T
header card
1
2
FREQ
SELECT
S1
Switch settings for 20 MHz
bus clock shown.
Table 2-1 Bus clock settings
Position 4
Position 3
Position 2
Position 1
BCLK (MHz)
On
On
On
On
4
On
On
On
Off
8
On
On
Off
On
16
On
On
Off
Off
20
