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AR# 51349: 14.2Place - ERROR:Place:1388 - Unroutable Placement! A BUFDS / GT clock component pair have been found that are not placed at a routable BUFDS / GT site pair.
14.2Place - ERROR:Place:1388 - Unroutable Placement! A BUFDS / GT clock component pair have been found that are not placed at a routable BUFDS / GT site pair.
I am trying to implement a Kintex-7 design but am receiving an error during implementation:
ERROR:Place:1388 - Unroutable Placement! A BUFDS / GT clock component pair have been found that are not placed at a routable BUFDS / GT site pair. The BUFDS component <i_jesd204_rx_block/i_gtwizard_v1_5_rx2_top/gt_usrclk_source/ibufds_instQ0_CL K1> is placed at site <IBUFDS_GTE2_X0Y5>. The GT component <i_jesd204_rx_block/i_gtwizard_v1_5_rx2_top/gtwizard_v1_5_rx2_i/gt0_gtwizard_ v1_5_rx2_i/gtxe2_i> is placed at site <GTXE2_CHANNEL_X0Y8>. The GT is driven by this BUFDS in regular mode and they must be placed in the same clock region to be routable because the BUFDS connects to the GT on a GTREFCLK pin. Furthermore, depending on the GTREFCLK bit used, only some BUFDS sites in the same clock region are routable to it. Check usage documents for routability of the device. This placement is UNROUTABLE in PAR and therefore, this error condition should be fixed in your design. You may use the CLOCK_DEDICATED_ROUTE constraint in the .ucf file to demote this message to a WARNING in order to generate an NCD file. This NCD file can then be used in FPGA Editor to debug the problem. A list of all the COMP.PINS used in this clock placement rule is listed below. These examples can be used directly in the .ucf file to demote this ERROR to a WARNING. < PIN "i_jesd204_rx_block/i_gtwizard_v1_5_rx2_top/gt_usrclk_source/ibufds_instQ0_CL K1.O" CLOCK_DEDICATED_ROUTE = FALSE; > < PIN "i_jesd204_rx_block/i_gtwizard_v1_5_rx2_top/gtwizard_v1_5_rx2_i/gt0_gtwizard_ v1_5_rx2_i/gtxe2_i.GTREFCLK0" CLOCK_DEDICATED_ROUTE = FALSE; >
In a Kintex-7 device, you can have 2 reference clocks for the GTXE2_CHANNEL component.
This needs to be driven by an IBUFDS_GTE2 component in the device.
In 7 series devices these IBUFDS_GTE2 components are arranged in pairs.
Only one pair can drive refclk0 on the GTXE2_CHANNEL and the other pair drives the refclk1 on the GTXE2_CHANNEL.
In the example generating the error, the IBUFDS_GTE2 refclk1 pair have been loc'd down to drive the refclk0 on the GTXE2_CHANNEL.
This is not routable and as a result the error is generated.
The work-around is to reverse the LOC constraints.
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