LC51024MV-52F484C Lattice, LC51024MV-52F484C Datasheet - Page 15

• Manufacturer Part Number: LC51024MV-52F484C
• Manufacturer: Lattice

Lattice Semiconductor
Clock Distribution
The ispXPLD 5000MX family has four dedicated clock input pins: GCLK0-GCLK3. GLCK0 and GCLK3 can be
routed through a PLL circuit or routed directly to the internal clock nets. The internal clock nets (CLK0-CLK3) are
directly related to the dedicated clock pins (see Secondary Clock Divider exception when using the sysCLOCK cir-
cuit). These feed the registers in the MFBs. Note at each register there is the option of inverting the clock if
required. Figure 14 shows the clock distribution network.
Figure 14. Clock Distribution Network
sysCLOCK PLL
The sysCLOCK PLL circuitry consists of Phase-Lock Loops (PLLs) and the various dividers, reset and feedback
signals associated with the PLLs. This feature gives the user the ability to synthesize clock frequencies and gener-
ate multiple clock signals for routing within the device. Furthermore, it can generate clock signals that are de-
skewed either at the board level or the device level.
The ispXPLD 5000MX devices provide two PLL circuits. PLL0 receives its clock inputs from GCLK 0 and provides
outputs to CLK 0 (CLK 1 when using the secondary clock). PLL1 operates with signals from GCLK 3 and CLK 3
(CLK 2 when using the secondary clock). The optional outputs CLK_OUT can be routed to an I/O pin. The optional
PLL_LOCK output is routed into the GRP. The optional input PLL_RST can be routed either from the GRP or
directly from an I/O pin. The optional PLL_FBK into can be routed directly from a pin. Figure 15 shows the ispXPLD
5000MX PLL block diagram. Figure 16 shows the connection of optional inputs and outputs.
GCLK0
GCLK1
GCLK2
GCLK3
VREF0
VREF1
VREF2
VREF3
sysCLOCK PLLs
PLL0
PLL1
CLK_OUT0
SEC_OUT0
SEC_OUT1
CLK_OUT1
15
Global Clock Routing
CLK0
CLK1
CLK2
CLK3
ispXPLD 5000MX Family Data Sheet
Clock Net
Clock Net
Clock Net
Clock Net
I/O/CLK_OUT0
I/O/CLK_OUT1
To Macrocells
To Macrocells
To Macrocells
To Macrocells