AX500-1BG896 ACTEL [Actel Corporation], AX500-1BG896 Datasheet - Page 80

• Manufacturer Part Number: AX500-1BG896
• Description: Axcelerator Family FPGAs
• Manufacturer: ACTEL [Actel Corporation]

Figure 2-51 • Feedback Clock Connections
CLK1 and CLK2
Both PLL outputs, CLK1 and CLK2, can be used to drive a
global resource, an adjacent PLL RefCLK input, or a net in
the FPGA core. Not all drive combinations are possible
(Table
Table 2-80 • PLL General Connections Rules
Restrictions on CLK1 and CLK2
Table 2-81
and CLK2 connections for the north and south PLLs.
HCLK1 and HCLK2 are used to denote the different HCLK
networks when two are being driven at the same time by
a single PLL (Note that HCLK1 is the primary clock
resource associated with the PLL, and HCLK2 is the clock
resource associated with the adjacent PLL). Likewise,
CLK1 and CLK2 are used to denote the different CLK
networks when two are being driven at the same time by
a single PLL
2 -6 6
CLK1
HCLK
CLK
HCLK
Routed net output
HCLK
NONE
CLK
NONE
Note: The PLL outputs remain Low when REFCLK is constant
Axcelerator Family FPGAs
• When both are driving global resources, they must
• Only one can drive a routed net at any given time.
be driving the same type of global resource (i.e.
either HCLK or CLK).
2-80).
(either Low or High).
and
(Figure 2-48 on page
FB
Any macro except HCLK macros
Table 2-82
PLL
PLLOUT/PLLRCLK
FB
specify all the possible CLK1
HCLK
CLK
Routed net output
HCLK
NONE
HCLK
NONE
CLK
2-63).
PLL
CLK2
v2.7
Table 2-81 • North PLL Connections
Table 2-82 • South PLL Connections
CLK1
HCLK1
HCLK1
HCLK2
HCLK2
HCLK2
HCLK2
Unused
Unused
Unused
Unused
Routed net
Routed net
Both HCLK1 and HCLK2
Both HCLK1 and HCLK2
Both HCLK1 and routed net
Both HCLK2 and routed net
Both HCLK2 and routed net
HCLK1, HCLK2, and routed net Unusable
Note: Designer software currently does not support all of these
CLK1
CLK1
CLK1
CLK2
CLK2
CLK2
CLK2
Unused
Unused
Unused
Unused
Routed net
Routed net
Both CLK1 and CLK2
Both CLK1 and CLK2
Both CLK1 and routed net
Both CLK2 and routed net
Both CLK2 and routed net
CLK1, CLK2, and routed net
Note: Designer software currently does not support all of these
connections. Only exclusive connections where one
output connects to a single net are supported at this time
(e.g.CLK1 driving HCLK1, and HCLK2 is not supported).
connections. Only exclusive connections where one
output connects to a single net are supported at this time
(e.g., CLK1 driving both CLK1 and CLK2 is not supported).
Routed net
Unused
HCLK1
Routed net
Both HCLK1 and routed net
Unused
HCLK1
Routed net
Both HCLK1 and routed net
Unused
HCLK1
Unused
Routed net
Unused
Unusable
HCLK1
Unused
Routed net
Unused
CLK1
Routed net
Both CLK1 and routed net
Unused
CLK1
Routed net
Both CLK1 and routed net
Unused
CLK1
Unused
Routed net
Unused
Unusable
CLK1
Unused
Unusable
CLK2
CLK2