Architecture
LatticeECP2/M Family Data Sheet
Lattice Semiconductor
Table 2-12. PIO Signals List
Name
Type
Description
CE0, CE1
CLK0, CLK1
ECLK1, ECLK2
LSR
Control from the core
Control from the core
Control from the core
Control from the core
Control from routing
Input to the core
Clock enables for input and output block flip-flops
System clocks for input and output blocks
Fast edge clocks
Local Set/Reset
GSRN
INCK2
Global Set/Reset (active low)
Input to Primary Clock Network or PLL reference inputs
DQS signal from logic (routing) to PIO
Unregistered data input to core
DQS
Input to PIO
INDD
Input to the core
INFF
Input to the core
Registered input on positive edge of the clock (CLK0)
Double data rate registered inputs to the core
Gearbox pipelined inputs to the core
Gearbox pipelined inputs to the core
IPOS0, IPOS1
Input to the core
QPOS01, QPOS11 Input to the core
QNEG01, QNEG11 Input to the core
OPOS0, ONEG0,
OPOS2, ONEG2
OPOS1 ONEG1
DEL[3:0]
Output data from the core
Output signals from the core for SDR and DDR operation
Tristate control from the core
Control from the core
Signals to Tristate Register block for DDR operation
Dynamic input delay control bits
TD
Tristate control from the core
Tristate signal from the core used in SDR operation
DDRCLKPOL
DQSXFER
Control from clock polarity bus Controls the polarity of the clock (CLK0) that feed the DDR input block
Control from core Controls signal to the Output block
1. Signals available on left/right/bottom only.
2. Selected I/O.
PIO
The PIO contains four blocks: an input register block, output register block, tristate register block and a control logic
block. These blocks contain registers for operating in a variety of modes along with the necessary clock and selec-
tion logic.
Input Register Block
The input register blocks for PIOs in left, right and bottom edges contain delay elements and registers that can be
used to condition high-speed interface signals, such as DDR memory interfaces and source synchronous inter-
faces, before they are passed to the device core. Figure 2-29 shows the diagram of the input register block for left,
right and bottom edges.The input register block for the top edge contains one memory element to register the input
signal as shown in Figure 2-30. The following description applies to the input register block for PIOs in the left, right
and bottom edges of the device.
Input signals are fed from the sysI/O buffer to the input register block (as signal DI). If desired, the input signal can
bypass the register and delay elements and be used directly as a combinatorial signal (INDD), a clock (INCK) and,
in selected blocks, the input to the DQS delay block. If an input delay is desired, designers can select either a fixed
delay or a dynamic delay DEL[3:0]. The delay, if selected, reduces input register hold time requirements when
using a global clock.
The input block allows three modes of operation. In the single data rate (SDR) the data is registered, by one of the
registers in the single data rate sync register block, with the system clock. In DDR Mode, two registers are used to
sample the data on the positive and negative edges of the DQS signal, creating two data streams, D0 and D1.
These two data streams are synchronized with the system clock before entering the core. Further discussion on
this topic is in the DDR Memory section of this data sheet.
2-31
LATTICE [ LATTICE SEMICONDUCTOR ]
