diff --git a/fuzzers/005-tilegrid/Makefile b/fuzzers/005-tilegrid/Makefile
index 38b5ee66..93dacc98 100644
--- a/fuzzers/005-tilegrid/Makefile
+++ b/fuzzers/005-tilegrid/Makefile
@@ -72,6 +72,7 @@ endif
 ifeq (${HAS_HIGH_PERFORMANCE_BANKS}, 1)
 TILEGRID_TDB_DEPENDENCIES += iob18/$(BUILD_FOLDER)/segbits_tilegrid.tdb
 TILEGRID_TDB_DEPENDENCIES += iob18_int/$(BUILD_FOLDER)/segbits_tilegrid.tdb
+TILEGRID_TDB_DEPENDENCIES += iob18_sing/$(BUILD_FOLDER)/segbits_tilegrid.tdb
 TILEGRID_TDB_DEPENDENCIES += ioi18/$(BUILD_FOLDER)/segbits_tilegrid.tdb
 # GTX transceiver fuzzers. Kintex-7 only: the xc7vx485t-ffg1761 package used for
 # virtex7 bonds only ~7 of its 14 GTX quads, so the unbonded GTX_COMMON tiles
@@ -129,6 +130,9 @@ iob_int/$(BUILD_FOLDER)/segbits_tilegrid.tdb: ${BASICDB_TILEGRID}
 iob18_int/$(BUILD_FOLDER)/segbits_tilegrid.tdb: ${BASICDB_TILEGRID}
 	cd iob18_int && $(MAKE)
 
+iob18_sing/$(BUILD_FOLDER)/segbits_tilegrid.tdb: ${BASICDB_TILEGRID}
+	cd iob18_sing && $(MAKE)
+
 ioi/$(BUILD_FOLDER)/segbits_tilegrid.tdb: ${BASICDB_TILEGRID}
 	cd ioi && $(MAKE)
 
@@ -233,6 +237,7 @@ clean:
 	cd iob18 && $(MAKE) clean
 	cd iob_int && $(MAKE) clean
 	cd iob18_int && $(MAKE) clean
+	cd iob18_sing && $(MAKE) clean
 	cd ioi && $(MAKE) clean
 	cd ioi18 && $(MAKE) clean
 	cd mmcm && $(MAKE) clean
@@ -270,6 +275,7 @@ clean_part:
 	cd iob18 && $(MAKE) clean_part
 	cd iob_int && $(MAKE) clean_part
 	cd iob18_int && $(MAKE) clean_part
+	cd iob18_sing && $(MAKE) clean_part
 	cd ioi && $(MAKE) clean_part
 	cd ioi18 && $(MAKE) clean_part
 	cd mmcm && $(MAKE) clean_part
diff --git a/fuzzers/005-tilegrid/iob18_sing/Makefile b/fuzzers/005-tilegrid/iob18_sing/Makefile
new file mode 100644
index 00000000..dd23257f
--- /dev/null
+++ b/fuzzers/005-tilegrid/iob18_sing/Makefile
@@ -0,0 +1,10 @@
+# Copyright (C) 2017-2020  The Project X-Ray Authors.
+#
+# Use of this source code is governed by a ISC-style
+# license that can be found in the LICENSE file or at
+# https://opensource.org/licenses/ISC
+#
+# SPDX-License-Identifier: ISC
+N ?= 14
+GENERATE_ARGS?="--oneval 1 --design params.csv --dframe 26 --dword 0"
+include ../fuzzaddr/common.mk
diff --git a/fuzzers/005-tilegrid/iob18_sing/generate.tcl b/fuzzers/005-tilegrid/iob18_sing/generate.tcl
new file mode 100644
index 00000000..d4f790b8
--- /dev/null
+++ b/fuzzers/005-tilegrid/iob18_sing/generate.tcl
@@ -0,0 +1,86 @@
+# Copyright (C) 2017-2020  The Project X-Ray Authors
+#
+# Use of this source code is governed by a ISC-style
+# license that can be found in the LICENSE file or at
+# https://opensource.org/licenses/ISC
+#
+# SPDX-License-Identifier: ISC
+source "$::env(XRAY_DIR)/utils/utils.tcl"
+
+proc make_io_pin_sites {} {
+    # get all possible IOB pins
+    foreach pad [get_package_pins -filter "IS_GENERAL_PURPOSE == 1"] {
+        set site [get_sites -of_objects $pad]
+        if {[llength $site] == 0} {
+            continue
+        }
+        if [string match IOB18* [get_property SITE_TYPE $site]] {
+            dict append io_pin_sites $site $pad
+        }
+    }
+    return $io_pin_sites
+}
+
+proc load_pin_lines {} {
+    # IOB_X0Y103 clk input
+    # IOB_X0Y129 do[0] output
+
+    set fp [open "params.csv" r]
+    gets $fp line
+
+    set pin_lines {}
+    for {gets $fp line} {$line != ""} {gets $fp line} {
+        lappend pin_lines [split $line ","]
+    }
+    close $fp
+    return $pin_lines
+}
+
+proc loc_pins {} {
+    set pin_lines [load_pin_lines]
+    set io_pin_sites [make_io_pin_sites]
+
+    puts "Looping"
+    for {set idx 0} {$idx < [llength $pin_lines]} {incr idx} {
+        set line [lindex $pin_lines $idx]
+        puts "$line"
+
+        set site_str [lindex $line 2]
+        set pin_str [lindex $line 3]
+
+        # Have: site
+        # Want: pin for site
+
+        set site [get_sites $site_str]
+        set pad_bel [get_bels -of_objects $site -filter {TYPE =~ PAD && NAME =~ IOB_*}]
+        # set port [get_ports -of_objects $site]
+        set port [get_ports $pin_str]
+        set tile [get_tiles -of_objects $site]
+
+        set pin [dict get $io_pin_sites $site]
+        set_property -dict "PACKAGE_PIN $pin IOSTANDARD LVCMOS18" $port
+    }
+}
+
+proc run {} {
+    create_project -force -part $::env(XRAY_PART) design design
+    read_verilog top.v
+    synth_design -top top
+
+    loc_pins
+
+    set_property CFGBVS GND [current_design]
+    set_property CONFIG_VOLTAGE 1.8 [current_design]
+    set_property BITSTREAM.GENERAL.PERFRAMECRC YES [current_design]
+    set_property IS_ENABLED 0 [get_drc_checks {REQP-79}]
+    set_property IS_ENABLED 0 [get_drc_checks {NSTD-1}]
+    set_property IS_ENABLED 0 [get_drc_checks {UCIO-1}]
+
+    place_design
+    route_design
+
+    write_checkpoint -force design.dcp
+    write_bitstream -force design.bit
+}
+
+run
diff --git a/fuzzers/005-tilegrid/iob18_sing/top.py b/fuzzers/005-tilegrid/iob18_sing/top.py
new file mode 100644
index 00000000..3fef5d49
--- /dev/null
+++ b/fuzzers/005-tilegrid/iob18_sing/top.py
@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+# Copyright (C) 2017-2020  The Project X-Ray Authors.
+#
+# Use of this source code is governed by a ISC-style
+# license that can be found in the LICENSE file or at
+# https://opensource.org/licenses/ISC
+#
+# SPDX-License-Identifier: ISC
+#
+# 005-tilegrid sub-fuzzer for SING-row IOB18 tiles.  The existing
+# iob18 sub-fuzzer filters to `IOB18S` (the main IOB of a diff pair)
+# and ioi18 explicitly skips `_SING` tile types, so the SING-row
+# IOB18 sites (one per LIOB18_SING / RIOB18_SING tile) never get
+# their tilegrid frame addresses resolved by the existing fuzzers.
+# This sub-fuzzer addresses that gap (task #17): place an IBUF on
+# every SING-row IOB18 site, then bit-diff produces a tdb that
+# add_tdb.py merges into tilegrid.json.
+import os
+import random
+random.seed(int(os.getenv("SEED"), 16))
+from prjxray import util
+from prjxray.db import Database
+
+
+def gen_sites():
+    '''SING-row IOB18 singleton sites: tile_type ends in _SING, site
+    type is plain IOB18 (no S/M suffix, no diff-pair partner).'''
+    db = Database(util.get_db_root(), util.get_part())
+    grid = db.grid()
+    for tile_name in sorted(grid.tiles()):
+        loc = grid.loc_of_tilename(tile_name)
+        gridinfo = grid.gridinfo_at_loc(loc)
+
+        if not gridinfo.tile_type.endswith("_SING"):
+            continue
+        # Skip non-IOB SING tiles (LIOI_SING etc.); only LIOB18_SING
+        # / RIOB18_SING expose an IOB18 site.
+        for site_name, site_type in gridinfo.sites.items():
+            if site_type == 'IOB18':
+                yield tile_name, site_name
+
+
+def write_params(params):
+    pinstr = 'tile,val,site,pin\n'
+    for tile, (site, val, pin) in sorted(params.items()):
+        pinstr += '%s,%s,%s,%s\n' % (tile, val, site, pin)
+    open('params.csv', 'w').write(pinstr)
+
+
+def run():
+    sites = list(gen_sites())
+    print(
+        '''
+`define N_DI {}
+
+module top(input wire [`N_DI-1:0] di);
+    wire [`N_DI-1:0] di_buf;
+    '''.format(len(sites)))
+
+    params = {}
+    print('''
+        (* KEEP, DONT_TOUCH *)
+        LUT6 dummy_lut();''')
+
+    for idx, ((tile_name, site_name), isone) in enumerate(zip(
+            sites, util.gen_fuzz_states(len(sites)))):
+        params[tile_name] = (site_name, isone, "di[%u]" % idx)
+        print(
+            '''
+    (* KEEP, DONT_TOUCH *)
+    IBUF #(
+    ) ibuf_{site_name} (
+        .I(di[{idx}]),
+        .O(di_buf[{idx}])
+        );'''.format(site_name=site_name, idx=idx))
+
+        if isone:
+            print(
+                '''
+    (* KEEP, DONT_TOUCH *)
+    PULLUP #(
+    ) pullup_{site_name} (
+        .O(di[{idx}])
+        );'''.format(site_name=site_name, idx=idx))
+
+    print("endmodule")
+    write_params(params)
+
+
+if __name__ == '__main__':
+    run()