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ECP5 and ECP5-5G sysCLOCK
PLL/DLL Design and Usage Guide
Internal Oscillator (OSCG)
The OSCG element performs multiple functions on the ECP5 and ECP5-5G device. It is used for configuration,
SED, as well as optionally in user mode. In user mode, the OSCG element has the following features:
• It permits a design to be fully self-clocked, as long as the quality of the OSCG element’s silicon-based oscillator
is adequate.
• If it’s unused it can be turned off for power savings.
• It has an input to dynamically control standby/normal operation.
• It has a direct connection to primary clock routing through the left mid-mux.
• It can be configured for operation at a wide range of frequencies via configuration bits.
OSCG Component Definition
The OSCG component can be instantiated in the source code of a design as defined in this section. Figure 15 and
Table 7 below show the OSCG definitions.
Figure 15. OSCG Component Symbol
Table 7. OSCG Component Port Definition
Table 8. OSCG Component Attribute Definition
OSCG Usage in VHDL
Component Instantiation
Library lattice;
use lattice.components.all;
Component and Attribute Declaration
component OSCG
Port (OSC : out STD_LOGIC);
end component;
OSCG Instantiation
I1: OSCG
port map (
OSC => OSC);
Port Name
I/O
Description
OSC
O
Clock Output Port
Name
Description
Value
Default
DI
V
Selects Divider
V
alue
2 (~155.0 MHz) – 128 (~2.4 MHz)
2.4 MHz
OSC
OSCG