
63
ECP5 and ECP5-5G Hi
g
h-Speed I/O Interface
Table 21. DLLDELD Attributes
Generic DDR Input and Output Primitives
The ECP5 and ECP5-5G device IDDR/ODDR modules support 2:1, 4:1 and 7:1 gearing modes on the left and right
sides only. IDDR/ODDR modules on the top (and bottom for non-SERDES parts) will only support 2:1 due to lack of
edge clocks. The 2:1 is available on each pin. The 4:1 gearing IDDR/ODDR is available on each pin on the left and
right. 7:1 gearing mode is only available per pin pair on the left and right. This means the DDR register of the N side
pin will be used to implement 7:1 mode and will not be available to the user. It is assumed that Generic DDR appli-
cations using 7:1 model will use a differential input so it would not require the DDR registers of the N side.
Input DDR Primitives
The following are the primitives used to implement various Generic DDR Input and Output data.
IDDRX1F
This primitive is used to receive Generic DDR with 1X gearing.
Figure 55. IDDDRX1F Primitive
Table 22. IDDRX1F Port List
IDDRX2F
This primitive is used to receive Generic DDR with 2X gearing.
Figure 56. IDDRX2F Primitive
Attribute
Description
Values
Default
DEL_ADJ
2
Sign bit for READ delay adjustment, DDR input
PLUS, MINUS
PLUS
DEL_VAL
2
Value of delay for input DDR.
0 to 255 (PLUS)
1 to 256 (MINUS)
Note
2
1. Attributes will only be available through EPIC and ECL Editor. It is recommended that values of this attribute are not updated without con-
sulting Lattice Semiconductor Technical Support.
2. Default value is set based on device characterization to achieve the 90 degree phase shift.
Port
I/O
Description
D
I
DDR data input
SCLK
I
Primary clock input
RST
I
Reset to DDR registers
Q0
O
Data at the positive edge of the clock
Q1
O
Data at the negative edge of the clock
IDDRX1F
SCLK
Q0
D
Q1
RST
Q1
SCLK
0
Q
D
RST
ALIGNWD
ECLK
Q2
Q3
IDDRX2F