User guide

Spartan-6 FPGA Configuration User Guide www.xilinx.com 153
UG380 (v2.7) October 29, 2014
SelectMAP ABORT
7. The Xilinx PROM must be set for parallel mode. This mode is available on the XCFxxP
devices.
8. When configuring a Spartan-6 device in SelectMAP mode from a Xilinx configuration
PROM, the RDWR_B and CSI_B signals can be tied Low (see SelectMAP Data Loading,
page 35).
9. Ganged SelectMAP configuration is specific to the Platform Flash XCFxxP PROM.
10. The CCLK net requires Thevenin parallel termination. See Board Layout for
Configuration Clock (CCLK), page 54.
If one device is designated as the Master, the DONE pins of all devices must be connected
with the active DONE drivers disabled. An external pull-up resistor is required on the
common DONE signal. Designers must carefully focus on signal integrity due to the
increased fanout of the outputs from the PROM. Signal integrity simulation is
recommended.
Readback is not possible if the CSI_B signals are tied together, because all devices
simultaneously attempt to drive the D signals.
SelectMAP ABORT
An ABORT is an interruption in the SelectMAP configuration or readback sequence
occurring when the state of RDWR_B changes while CSI_B is asserted. During a
configuration ABORT, internal status is driven onto the D[7:4] pins over the next four
CCLK cycles. The other D pins are always High. After the ABORT sequence finishes, the
user can resynchronize the configuration logic and resume configuration. For applications
that must deassert RDWR_B between bytes, see Accessing Configuration Registers
through the SelectMAP Interface, page 116.
Configuration Abort Sequence Description
An ABORT is signaled during configuration as follows:
1. The configuration sequence begins normally.
2. The user pulls the RDWR_B pin High while the device is selected (CSI_B asserted
Low).
3. BUSY goes High if CSI_B remains asserted (Low). The FPGA drives the status word
onto the data pins if RDWR_B remains set for read control (logic High).
4. The ABORT lasts for four clock cycles, and Status is updated.
X-Ref Target - Figure 9-6
Figure 9-6: Configuration Abort Sequence for SelectMAP Modes
D[0:7]
BUSY
CCLK
STAT US
ABORT
UG380_c9_06_021710
CSI_B
RDWR_B