Zynq-7000 AP SoC and 7 Series FPGAs MIS v4.1
136
UG586 November 30, 2016
Chapter 1:
DDR3 and DDR2 SDRAM Memory Interface Solution
The PHY control interface is used by the calibration logic or the Memory Controller to write
PHY control words to the PHY. The signals in this interface are synchronous to the PHY_Clk
and are listed in
. This is a basic FIFO style interface. Control words are written
into the control word FIFO on the rising edge of PHY_Clk when PHY_Ctl_WrEn is High and
PHY_Ctl_Full is Low. For multi-I/O bank PHYs, the same control word must be written into
each PHY control block for proper operation.
The PHY control word is broken down into several fields, as shown in
•
PHY Command
– This field defines the actions undertaken by the PHY control block to
manage command and data flow through the dedicated PHY. The PHY commands are:
°
Write
(Wr – 0x01)
– This command instructs the PHY control block to read the
address, command, and data OUT_FIFOs and transfer the data read from those
FIFOs to their associated IOIs.
°
Read
(Rd – 0x03)
– This command instructs the PHY control block to read the
address, command OUT_FIFOs, and transfer the data read from those FIFOs to their
associated IOIs. In addition, data read from the memory is transferred after its
arrival from the data IOIs to the Data IN_FIFO.
°
Non-Data
(ND – 0x04)
– This command instructs the PHY control block to read the
address and command OUT_FIFOs and transfer the data read from those FIFOs to
their associated IOIs.
Table 1-57:
PHY Control Interface
Signal
Direction
Description
PHY_Clk
Input
This is the PHY interface clock for the control word FIFO. PHY control word
signals are captured on the rising edge of this clock.
PHY_Ctl_Wr_N
Input
This active-Low signal is the write enable signal for the control word FIFO.
A control word is written into the control word FIFO on the rising edge of
PHY_Clk, when this signal is active.
PHY_Ctl_Wd[31:0]
Input
This is the PHY control word described in
.
PHY_Ctl_Full
Output
This active-High output is the full flag for the control word FIFO. It indicates
that the FIFO cannot accept anymore control words and blocks writes to the
control word FIFO.
PHY_Ctl_AlmostFull
Output
This active-High output is the almost full flag for the control word FIFO. It
indicates that the FIFO can accept no more than one additional control
word as long as the PHY_Ctl_Full signal is inactive.
PHY_Ctl_Ready
Output
This active-High output becomes set when the PHY control block is ready
to start receiving commands.
Table 1-58:
PHY Control Word
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0 9 8 7 6 5 4 3 2 1 0
Act
Pre
Event
Delay
CAS
Slot
Seq
Data Offset
Reser
ved
Low
Index
Aux_Out
Control Offset PHY Cmd