diff --git a/README b/README
index d27eee8..b85ead3 100644
--- a/README
+++ b/README
@@ -5,16 +5,13 @@ Introduction
  block ram and multiply-accumulate devices.
  The long-term goals of fpgatools are:
 
- *) reach the maximum physical performance of the chip
+ *) reach maximum physical chip performance
  *) fast development cycles
  *) independent toolchain that only depends on other free software
- *) bootstrap on chip, i.e. program the fpga from a softcore running
-    on the same fpga
- *) complete package including all tools to get started such as jtag,
-    debugging, parts data and designs for prototyping hardware
- *) work towards a design flow that includes later manufacturing
-    in different ASIC processes, include information about ASIC
-    processes, libraries, GDS generation, etc.
+ *) reconfigure on-chip
+ *) include get-started tools such as jtag, debugging, parts data
+    and designs for prototyping hardware
+ *) design flow that includes asic manufacturing
  *) lightweight C implementation without GUI
  *) supported platform: Linux
  *) license: public domain
@@ -59,13 +56,9 @@ Design Principles
 TODO
 
 short-term (1 month):
-* add lut_encoding autotest for lut6 and lut5 in a-d position
-  of x(m), x(l), l and m devs
-* more cases in logic_cfg test
 * example: blinking_led
 * example: counter (including clock, jtag)
-* support reading iologic switches
-* autotest: fix roundtrip issues in routing_sw test
+* autotest: fix bugs in lut_encoding, logic_cfg, routing_sw, io_sw tests
 * autotest: protect stderr of diff executable in autotest log
 * 3 Debian packages: libfpga, libfpga-doc, fpgatools
 
diff --git a/autotest.c b/autotest.c
index a63ef34..1444ca9 100644
--- a/autotest.c
+++ b/autotest.c
@@ -957,6 +957,22 @@ static int test_iob_config(struct test_state* tstate)
 
 		i++;
 	}}
+	// enum all iobs
+	{
+		const char* name;
+		for (i = 0; (name = fpga_enum_iob(tstate->model, i, &iob_y,
+			&iob_x, &iob_type_idx)); i++) {
+			if (tstate->dry_run)
+				printf("IOB %s y%02i x%02i i%i\n", name,
+					iob_y, iob_x, iob_type_idx);
+			rc = fdev_iob_IMUX(tstate->model, iob_y, iob_x,
+				iob_type_idx, IMUX_I);
+			if (rc) FAIL(rc);
+			if ((rc = diff_printf(tstate))) FAIL(rc);
+			fdev_delete(tstate->model, iob_y, iob_x,
+				DEV_IOB, iob_type_idx);
+		}
+	}
 	return 0;
 fail:
 	return rc;
diff --git a/blinking_led.c b/blinking_led.c
index 44dba8d..b844d33 100644
--- a/blinking_led.c
+++ b/blinking_led.c
@@ -22,43 +22,73 @@
      assign led = counter[14];
 
    endmodule
-
 */
 
 int main(int argc, char** argv)
 {
 	struct fpga_model model;
-	int iob_inA_y, iob_inA_x, iob_inA_type_idx;
-	int iob_inB_y, iob_inB_x, iob_inB_type_idx;
-	int iob_out_y, iob_out_x, iob_out_type_idx;
+	int iob_clk_y, iob_clk_x, iob_clk_type_idx;
+	int iob_led_y, iob_led_x, iob_led_type_idx;
 	int logic_y, logic_x, logic_type_idx;
+	struct fpgadev_logic logic_cfg;
 	net_idx_t inA_net, inB_net, out_net;
-	int rc;
 
-	if ((rc = fpga_build_model(&model, XC6SLX9_ROWS, XC6SLX9_COLUMNS,
-		XC6SLX9_LEFT_WIRING, XC6SLX9_RIGHT_WIRING))) FAIL(rc);
+	fpga_build_model(&model, XC6SLX9_ROWS, XC6SLX9_COLUMNS,
+		XC6SLX9_LEFT_WIRING, XC6SLX9_RIGHT_WIRING);
 
-	if ((rc = fpga_find_iob(&model, "P45", &iob_inA_y, &iob_inA_x,
-		&iob_inA_type_idx))) FAIL(rc);
-	if ((rc = fdev_iob_input(&model, iob_inA_y, iob_inA_x,
-		iob_inA_type_idx, IO_LVCMOS33))) FAIL(rc);
+	fpga_find_iob(&model, "P55", &iob_clk_y, &iob_clk_x, &iob_clk_type_idx);
+	fdev_iob_input(&model, iob_clk_y, iob_clk_x, iob_clk_type_idx,
+		IO_LVCMOS33);
 
-	if ((rc = fpga_find_iob(&model, "P46", &iob_inB_y, &iob_inB_x,
-		&iob_inB_type_idx))) FAIL(rc);
-	if ((rc = fdev_iob_input(&model, iob_inB_y, iob_inB_x,
-		iob_inB_type_idx, IO_LVCMOS33))) FAIL(rc);
-
-	if ((rc = fpga_find_iob(&model, "P48", &iob_out_y, &iob_out_x,
-		&iob_out_type_idx))) FAIL(rc);
-	if ((rc = fdev_iob_output(&model, iob_out_y, iob_out_x,
-		iob_out_type_idx, IO_LVCMOS33))) FAIL(rc);
+	fpga_find_iob(&model, "P48", &iob_led_y, &iob_led_x, &iob_led_type_idx);
+	fdev_iob_output(&model, iob_led_y, iob_led_x, iob_led_type_idx,
+		IO_LVCMOS25);
+	fdev_iob_slew(&model, iob_led_y, iob_led_x, iob_led_type_idx,
+		SLEW_QUIETIO);
+	fdev_iob_drive(&model, iob_led_y, iob_led_x, iob_led_type_idx,
+		8);
 
+#if 0
 	logic_y = 68;
 	logic_x = 13;
 	logic_type_idx = DEV_LOG_X;
 	if ((rc = fdev_logic_a2d_lut(&model, logic_y, logic_x, logic_type_idx,
 		LUT_D, 6, "A3*A5", ZTERM))) FAIL(rc);
 
+			memset(&logic_cfg, 0, sizeof(logic_cfg));
+			logic_cfg.a2d[LUT_A].lut6 = "(A6+~A6)*(~A5)";
+			logic_cfg.a2d[LUT_A].lut5 = "1";
+			logic_cfg.a2d[LUT_A].cy0 = CY0_O5;
+			logic_cfg.a2d[LUT_A].ff = FF_FF;
+			logic_cfg.a2d[LUT_A].ff_mux = MUX_XOR;
+			logic_cfg.a2d[LUT_A].ff_srinit = FF_SRINIT0;
+			logic_cfg.a2d[LUT_B].lut6 = "(A6+~A6)*(A5)";
+			logic_cfg.a2d[LUT_B].lut5 = "1";
+			logic_cfg.a2d[LUT_B].cy0 = CY0_O5;
+			logic_cfg.a2d[LUT_B].ff = FF_FF;
+			logic_cfg.a2d[LUT_B].ff_mux = MUX_XOR;
+			logic_cfg.a2d[LUT_B].ff_srinit = FF_SRINIT0;
+			logic_cfg.a2d[LUT_C].lut6 = "(A6+~A6)*(A5)";
+			logic_cfg.a2d[LUT_C].lut5 = "1";
+			logic_cfg.a2d[LUT_C].cy0 = CY0_O5;
+			logic_cfg.a2d[LUT_C].ff = FF_FF;
+			logic_cfg.a2d[LUT_C].ff_mux = MUX_XOR;
+			logic_cfg.a2d[LUT_C].ff_srinit = FF_SRINIT0;
+			logic_cfg.a2d[LUT_D].lut6 = "(A6+~A6)*(A5)";
+			logic_cfg.a2d[LUT_D].lut5 = "1";
+			logic_cfg.a2d[LUT_D].cy0 = CY0_O5;
+			logic_cfg.a2d[LUT_D].ff = FF_FF;
+			logic_cfg.a2d[LUT_D].ff_mux = MUX_XOR;
+			logic_cfg.a2d[LUT_D].ff_srinit = FF_SRINIT0;
+
+			logic_cfg.clk_inv = CLKINV_CLK;
+			logic_cfg.sync_attr = SYNCATTR_ASYNC;
+			logic_cfg.precyinit = PRECYINIT_0;
+			logic_cfg.cout_used = 1;
+	rc = fdev_logic_setconf(tstate->model, y, x, type_idx, logic_cfg);
+	if (rc) FAIL(rc);
+
+
 	if ((rc = fnet_new(&model, &inA_net))) FAIL(rc);
 	if ((rc = fnet_add_port(&model, inA_net, iob_inA_y, iob_inA_x,
 		DEV_IOB, iob_inA_type_idx, IOB_OUT_I))) FAIL(rc);
@@ -79,9 +109,8 @@ int main(int argc, char** argv)
 	if ((rc = fnet_add_port(&model, out_net, iob_out_y, iob_out_x,
 		DEV_IOB, iob_out_type_idx, IOB_IN_O))) FAIL(rc);
 	if ((rc = fnet_autoroute(&model, out_net))) FAIL(rc);
+#endif
 
-	if ((rc = write_floorplan(stdout, &model, FP_DEFAULT))) FAIL(rc);
-	return EXIT_SUCCESS;
-fail:
-	return rc;
+	write_floorplan(stdout, &model, FP_DEFAULT);
+	return fpga_free_model(&model);
 }
diff --git a/libs/control.c b/libs/control.c
index ddf2731..365b763 100644
--- a/libs/control.c
+++ b/libs/control.c
@@ -163,7 +163,7 @@ const char* fpga_iob_sitename(struct fpga_model* model, int y, int x,
 
 	if (y == TOP_OUTER_ROW) {
 		for (i = 0; i < sizeof(xc6slx9_iob_top)/sizeof(xc6slx9_iob_top[0]); i++) {
-			if (xc6slx9_iob_right[i].xy == x) {
+			if (xc6slx9_iob_top[i].xy == x) {
 				if (idx < 0 || idx > 3) return 0;
 				return xc6slx9_iob_top[i].name[idx];
 			}
@@ -798,6 +798,60 @@ fail:
 	return rc;
 }
 
+int fdev_iob_IMUX(struct fpga_model* model, int y, int x,
+	int type_idx, int mux)
+{
+	struct fpga_device* dev;
+	int rc;
+
+	dev = fdev_p(model, y, x, DEV_IOB, type_idx);
+	if (!dev) FAIL(EINVAL);
+	rc = reset_required_pins(dev);
+	if (rc) FAIL(rc);
+
+	dev->u.iob.I_mux = mux;
+	dev->instantiated = 1;
+	return 0;
+fail:
+	return rc;
+}
+
+int fdev_iob_slew(struct fpga_model* model, int y, int x,
+	int type_idx, int slew)
+{
+	struct fpga_device* dev;
+	int rc;
+
+	dev = fdev_p(model, y, x, DEV_IOB, type_idx);
+	if (!dev) FAIL(EINVAL);
+	rc = reset_required_pins(dev);
+	if (rc) FAIL(rc);
+
+	dev->u.iob.slew = slew;
+	dev->instantiated = 1;
+	return 0;
+fail:
+	return rc;
+}
+
+int fdev_iob_drive(struct fpga_model* model, int y, int x,
+	int type_idx, int drive_strength)
+{
+	struct fpga_device* dev;
+	int rc;
+
+	dev = fdev_p(model, y, x, DEV_IOB, type_idx);
+	if (!dev) FAIL(EINVAL);
+	rc = reset_required_pins(dev);
+	if (rc) FAIL(rc);
+
+	dev->u.iob.drive_strength = drive_strength;
+	dev->instantiated = 1;
+	return 0;
+fail:
+	return rc;
+}
+
 static void scan_lut_digits(const char* s, int* digits)
 {
 	int i;
diff --git a/libs/control.h b/libs/control.h
index ce756cb..8068259 100644
--- a/libs/control.h
+++ b/libs/control.h
@@ -87,6 +87,12 @@ int fdev_iob_input(struct fpga_model* model, int y, int x,
 	int type_idx, const char* io_std);
 int fdev_iob_output(struct fpga_model* model, int y, int x,
 	int type_idx, const char* io_std);
+int fdev_iob_IMUX(struct fpga_model* model, int y, int x,
+	int type_idx, int mux);
+int fdev_iob_slew(struct fpga_model* model, int y, int x,
+	int type_idx, int slew);
+int fdev_iob_drive(struct fpga_model* model, int y, int x,
+	int type_idx, int drive_strength);
 
 int fdev_set_required_pins(struct fpga_model* model, int y, int x, int type,
 	int type_idx);
diff --git a/libs/floorplan.c b/libs/floorplan.c
index 4ce2064..d655f29 100644
--- a/libs/floorplan.c
+++ b/libs/floorplan.c
@@ -1051,6 +1051,10 @@ int write_floorplan(FILE* f, struct fpga_model* model, int flags)
 
 	if (!(flags & FP_NO_HEADER))
 		printf_version(f);
+	if (model->rc) {
+		fprintf(f, "rc %i\n", model->rc);
+		FAIL(model->rc);
+	}
 
 	rc = printf_devices(f, model, /*config_only*/ 1);
 	if (rc) FAIL(rc);
diff --git a/libs/model.h b/libs/model.h
index 66b6722..bc66bd4 100644
--- a/libs/model.h
+++ b/libs/model.h
@@ -54,6 +54,8 @@
 
 struct fpga_model
 {
+	int rc; // if rc != 0, all function calls will immediately return
+
 	int cfg_rows;
 	char cfg_columns[512];
 	char cfg_left_wiring[1024], cfg_right_wiring[1024];
@@ -585,7 +587,8 @@ struct fpga_tile
 int fpga_build_model(struct fpga_model* model,
 	int fpga_rows, const char* columns,
 	const char* left_wiring, const char* right_wiring);
-void fpga_free_model(struct fpga_model* model);
+// returns model->rc (model itself will be memset to 0)
+int fpga_free_model(struct fpga_model* model);
 
 const char* fpga_tiletype_str(enum fpga_tile_type type);
 
diff --git a/libs/model_main.c b/libs/model_main.c
index 67148f0..128b252 100644
--- a/libs/model_main.c
+++ b/libs/model_main.c
@@ -57,15 +57,19 @@ fail:
 	return rc;
 }
 
-void fpga_free_model(struct fpga_model* model)
+int fpga_free_model(struct fpga_model* model)
 {
-	if (!model) return;
+	int rc;
+
+	if (!model) return 0;
+	rc = model->rc;
 	free_devices(model);
 	free(model->tmp_str);
 	strarray_free(&model->str);
 	free(model->tiles);
 	free_xc6_routing_bitpos(model->sw_bitpos);
 	memset(model, 0, sizeof(*model));
+	return rc;
 }
 
 static const char* fpga_ttstr[] = // tile type strings