Architecture
LatticeECP/EC Family Data Sheet
Lattice Semiconductor
For further information about the sysDSP block, please see the list of technical information at the end of this data
sheet.
Programmable I/O Cells (PIC)
Each PIC contains two PIOs connected to their respective sysI/O Buffers which are then connected to the PADs as
shown in Figure 2-24. The PIO Block supplies the output data (DO) and the Tri-state control signal (TO) to sysI/O
buffer, and receives input from the buffer.
Figure 2-24. PIC Diagram
PIO A
TD
D0
D1
TD
OPOS1
ONEG1
IOLT0
DDRCLK
Tristate
Register Block
(2 Flip Flops)
PADA
"T"
D0
D1
OPOS0
ONEG0
DDRCLK
IOLD0
Output
Register Block
(2 Flip Flops)
sysIO
Buffer
INCK
INDD
INFF
IPOS0
IPOS1
INCK
INDD
INFF
IPOS0
IPOS1
DI
Control
Muxes
Input
Register Block
(5 Flip Flops)
CLKO
CEO
LSR
CLK
CE
LSR
GSRN
GSR
CLKI
CEI
DQS
DDRCLKPOL
PADB
"C"
PIO B
Two adjacent PIOs can be joined to provide a differential I/O pair (labeled as “T” and “C”) as shown in Figure 2-25.
The PAD Labels “T” and “C” distinguish the two PIOs. Only the PIO pairs on the left and right edges of the device
can be configured as LVDS transmit/receive pairs.
One of every 16 PIOs contains a delay element to facilitate the generation of DQS signals. The DQS signal feeds
the DQS bus which spans the set of 16 PIOs. Figure 2-25 shows the assignment of DQS pins in each set of 16
PIOs.The exact DQS pins are shown in a dual function in the Logic Signal Connections table at the end of this data
sheet. Additional detail is provided in the Signal Descriptions table at the end of this data sheet. The DQS signal
from the bus is used to strobe the DDR data from the memory into input register blocks. This interface is designed
for memories that support one DQS strobe per eight bits of data.
2-21
LATTICE [ LATTICE SEMICONDUCTOR ]
