Spectrum Digital eZdsp R2812 USB, Technical Reference, Page: 31 / 46

Spectrum Digital, Inc
2-19
2.5 Switch SW501
The eZdsp R2812 has a 4 position switch that allows the user to configure the board for
their application. The function of each position is shown in the table below.
2.5.1 Switch SW501, Position 1, PLL Enable/Disable
Position 1 on switch SW501 is used to enable/disable the use of the Phase Lock Loop
(PLL) logic on the DSP. The selection of the open position enables the use of the PLL.
If the closed position is used the PLL is disabled. This signal is latched at reset and
may be used as XF after reset. The positions are shown in the table below.
* as shipped from the factory
Table 13: SW501 Switch Positions
Position Function
1 PLL Enable/Disable
2 MP/MC Select
3, 4 Boot Mode Select
Table 14: SW501, Position 1
Position Function
Open-1 * PLL Enabled
Closed-0 PLL disabled
SW
5
0
1
Open/High | Closed/Low
XF_XPLLDISn
XMP_MCn
SPICLKA
MDXA
Default from factory
Figure 2-13, SW501 Layout
1
2
3
4