DS617 Datasheet, PDF (24/88 Pages) Xilinx, Inc – MultiBoot Bitstream, Design Revision Storage

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Platform Flash XL High-Density Configuration and Storage Device
Configuration Register
The Configuration Register is used to configure the type of bus access that the memory performs. Refer to "Read Modes,"
page 34 for details on read operations.
The Configuration Register is set through the Command Interface using the Set Configuration Register command. After a
reset or power-up, the device is configured for Synchronous Read (CR15 = 0). The Configuration Register bits (Table 12,
page 26) specify the selection of the burst length, burst type, burst X latency, and read operation. Refer to Figure 9, page 28
and Figure 10, page 30 for examples of synchronous burst configurations.
Table 12: Configuration Register Bits
Bits
Description
Value
Description
CR15
Read mode
0
Synchronous Read (default)
1
Asynchronous Read
CR14
Reserved
0
010
2 clock latency⁽¹⁾
011
3 clock latency
100
4 clock latency
CR13–CR11
Clock Latency
101
5 clock latency
110
6 clock latency
111
7 clock latency (default)
Other configurations reserved
CR10
Wait Polarity
0
READY_WAIT with Wait function (CR4 = 0) is active Low
1
READY_WAIT with Wait function (CR4 = 0) is active High (default)
CR9
Data output
configuration
0
Data held for 1 clock cycle (default)
1
Data held for 2 clock cycles⁽¹⁾
CR8
Wait Configuration
0
Wait active during wait state
1
Wait active 1 clock cycle before wait state (default)
CR7
Burst Type
0
Reserved
1
Sequential (default)
CR6
Valid Clock Edge
0
Falling clock edge
1
Rising clock edge (default)
CR5
Reserved
0
–
CR4
Device_ready
0
READY_WAIT signal has the Wait function
1
READY_WAIT signal has the Ready function (default)
CR3⁽²⁾
Wrap burst
0
Wrap
1
No wrap (default)
001
4 words
CR2–CR0⁽²⁾
Burst Length
010
8 words
011
16 words
111
Continuous (default)
Notes:
1. The combination X-Latency = 2, Data held for two clock cycles and Wait active one data cycle before the WAIT state is not supported.
2. CR3 (wrap/no wrap) bit has no effect when CR2-CR0 (burst length) bits are set to continuous burst mode. Platform Flash XL wraps to the first
memory address after the device outputs the data from the last memory address.
DS617 (v3.0.1) January 07, 2010
www.xilinx.com
Product Specification
24