diff --git a/build/final.elf b/build/final.elf
index b9785a1..4974603 100755
Binary files a/build/final.elf and b/build/final.elf differ
diff --git a/build/final.elf.map b/build/final.elf.map
index 5718856..2a42ce1 100644
--- a/build/final.elf.map
+++ b/build/final.elf.map
@@ -18,6 +18,8 @@ Discarded input sections
  .text          0x00000000        0x0 build/gpio.o
  .data          0x00000000        0x0 build/gpio.o
  .bss           0x00000000        0x0 build/gpio.o
+ .text.gpio_set_af
+                0x00000000       0x98 build/gpio.o
  .group         0x00000000        0xc build/main.o
  .group         0x00000000        0xc build/main.o
  .group         0x00000000        0xc build/main.o
@@ -261,38 +263,38 @@ LOAD build/timer.o
 OUTPUT(build/final.elf elf32-littlearm)
 LOAD linker stubs
 
-.debug_info     0x00000000      0xb10
- .debug_info    0x00000000      0x205 build/gpio.o
- .debug_info    0x00000205      0x44e build/main.o
- .debug_info    0x00000653      0x188 build/startup.o
- .debug_info    0x000007db      0x335 build/timer.o
+.debug_info     0x00000000      0xb6d
+ .debug_info    0x00000000      0x262 build/gpio.o
+ .debug_info    0x00000262      0x44e build/main.o
+ .debug_info    0x000006b0      0x188 build/startup.o
+ .debug_info    0x00000838      0x335 build/timer.o
 
-.debug_abbrev   0x00000000      0x439
- .debug_abbrev  0x00000000      0x119 build/gpio.o
- .debug_abbrev  0x00000119      0x144 build/main.o
- .debug_abbrev  0x0000025d      0x127 build/startup.o
- .debug_abbrev  0x00000384       0xb5 build/timer.o
+.debug_abbrev   0x00000000      0x43d
+ .debug_abbrev  0x00000000      0x11d build/gpio.o
+ .debug_abbrev  0x0000011d      0x144 build/main.o
+ .debug_abbrev  0x00000261      0x127 build/startup.o
+ .debug_abbrev  0x00000388       0xb5 build/timer.o
 
-.debug_aranges  0x00000000       0xa8
+.debug_aranges  0x00000000       0xb0
  .debug_aranges
-                0x00000000       0x28 build/gpio.o
+                0x00000000       0x30 build/gpio.o
  .debug_aranges
-                0x00000028       0x28 build/main.o
+                0x00000030       0x28 build/main.o
  .debug_aranges
-                0x00000050       0x30 build/startup.o
+                0x00000058       0x30 build/startup.o
  .debug_aranges
-                0x00000080       0x28 build/timer.o
+                0x00000088       0x28 build/timer.o
 
 .debug_rnglists
-                0x00000000       0x6c
+                0x00000000       0x73
  .debug_rnglists
-                0x00000000       0x19 build/gpio.o
+                0x00000000       0x20 build/gpio.o
  .debug_rnglists
-                0x00000019       0x1b build/main.o
+                0x00000020       0x1b build/main.o
  .debug_rnglists
-                0x00000034       0x1f build/startup.o
+                0x0000003b       0x1f build/startup.o
  .debug_rnglists
-                0x00000053       0x19 build/timer.o
+                0x0000005a       0x19 build/timer.o
 
 .debug_macro    0x00000000     0x3ba0
  .debug_macro   0x00000000      0xb56 build/gpio.o
@@ -321,20 +323,20 @@ LOAD linker stubs
  .debug_macro   0x00002f20      0xb5c build/timer.o
  .debug_macro   0x00003a7c      0x124 build/timer.o
 
-.debug_line     0x00000000      0x4b3
- .debug_line    0x00000000      0x116 build/gpio.o
- .debug_line    0x00000116      0x1d4 build/main.o
- .debug_line    0x000002ea       0xea build/startup.o
- .debug_line    0x000003d4       0xdf build/timer.o
+.debug_line     0x00000000      0x516
+ .debug_line    0x00000000      0x179 build/gpio.o
+ .debug_line    0x00000179      0x1d4 build/main.o
+ .debug_line    0x0000034d       0xea build/startup.o
+ .debug_line    0x00000437       0xdf build/timer.o
 
-.debug_str      0x00000000     0x5eba
- .debug_str     0x00000000     0x5375 build/gpio.o
-                               0x551d (size before relaxing)
- .debug_str     0x00005375      0xab1 build/main.o
+.debug_str      0x00000000     0x5ed0
+ .debug_str     0x00000000     0x538b build/gpio.o
+                               0x553b (size before relaxing)
+ .debug_str     0x0000538b      0xab1 build/main.o
                                0x5f7e (size before relaxing)
- .debug_str     0x00005e26       0x88 build/startup.o
+ .debug_str     0x00005e3c       0x88 build/startup.o
                                0x3cdc (size before relaxing)
- .debug_str     0x00005eae        0xc build/timer.o
+ .debug_str     0x00005ec4        0xc build/timer.o
                                0x5b16 (size before relaxing)
 
 .comment        0x00000000       0x45
@@ -370,8 +372,8 @@ LOAD linker stubs
                 0x00000278        0x8 build/timer.o
                                 0x25b (size before relaxing)
 
-.debug_frame    0x00000000      0x16c
- .debug_frame   0x00000000       0x60 build/gpio.o
- .debug_frame   0x00000060       0x50 build/main.o
- .debug_frame   0x000000b0       0x6c build/startup.o
- .debug_frame   0x0000011c       0x50 build/timer.o
+.debug_frame    0x00000000      0x194
+ .debug_frame   0x00000000       0x88 build/gpio.o
+ .debug_frame   0x00000088       0x50 build/main.o
+ .debug_frame   0x000000d8       0x6c build/startup.o
+ .debug_frame   0x00000144       0x50 build/timer.o
diff --git a/build/gpio.S b/build/gpio.S
index 499cfd0..9e89fa0 100644
--- a/build/gpio.S
+++ b/build/gpio.S
@@ -102,16 +102,16 @@ gpio_set_mode:
 	.cfi_endproc
 .LFE0:
 	.size	gpio_set_mode, .-gpio_set_mode
-	.section	.text.gpio_write,"ax",%progbits
+	.section	.text.gpio_set_af,"ax",%progbits
 	.align	1
-	.global	gpio_write
+	.global	gpio_set_af
 	.syntax unified
 	.thumb
 	.thumb_func
-	.type	gpio_write, %function
-gpio_write:
+	.type	gpio_set_af, %function
+gpio_set_af:
 .LFB1:
-	.loc 1 13 40
+	.loc 1 13 44
 	.cfi_startproc
 	@ args = 0, pretend = 0, frame = 16
 	@ frame_needed = 1, uses_anonymous_args = 0
@@ -138,30 +138,80 @@ gpio_write:
 	lsls	r3, r3, #10
 	.loc 1 14 16
 	str	r3, [r7, #12]
-	.loc 1 15 32
+	.loc 1 15 17
 	ldrh	r3, [r7, #6]
+	.loc 1 15 7
 	and	r3, r3, #15
-	.loc 1 15 24
-	movs	r2, #3
-	lsls	r2, r2, r3
-	.loc 1 15 55
-	ldrb	r3, [r7, #5]	@ zero_extendqisi2
-	cmp	r3, #0
-	beq	.L3
-	.loc 1 15 55 is_stmt 0 discriminator 1
-	movs	r3, #0
-	b	.L4
-.L3:
-	.loc 1 15 55 discriminator 2
-	movs	r3, #16
-.L4:
-	.loc 1 15 43 is_stmt 1 discriminator 4
-	lsl	r3, r2, r3
-	mov	r2, r3
-	.loc 1 15 14 discriminator 4
+	str	r3, [r7, #8]
+	.loc 1 16 6
+	ldr	r3, [r7, #8]
+	cmp	r3, #7
+	bgt	.L3
+	.loc 1 17 6
 	ldr	r3, [r7, #12]
-	str	r2, [r3, #24]
-	.loc 1 16 1 discriminator 4
+	ldr	r3, [r3, #32]
+	.loc 1 17 32
+	ldr	r2, [r7, #8]
+	lsls	r2, r2, #2
+	.loc 1 17 25
+	movs	r1, #15
+	lsl	r2, r1, r2
+	.loc 1 17 16
+	mvns	r2, r2
+	.loc 1 17 13
+	ands	r2, r2, r3
+	ldr	r3, [r7, #12]
+	str	r2, [r3, #32]
+	.loc 1 18 6
+	ldr	r3, [r7, #12]
+	ldr	r3, [r3, #32]
+	.loc 1 18 20
+	ldrb	r2, [r7, #5]	@ zero_extendqisi2
+	and	r1, r2, #15
+	.loc 1 18 37
+	ldr	r2, [r7, #8]
+	lsls	r2, r2, #2
+	.loc 1 18 30
+	lsl	r2, r1, r2
+	.loc 1 18 13
+	orrs	r2, r2, r3
+	ldr	r3, [r7, #12]
+	str	r2, [r3, #32]
+	.loc 1 23 1
+	b	.L5
+.L3:
+	.loc 1 20 6
+	ldr	r3, [r7, #12]
+	ldr	r3, [r3, #36]
+	.loc 1 20 32
+	ldr	r2, [r7, #8]
+	lsls	r2, r2, #2
+	.loc 1 20 25
+	movs	r1, #15
+	lsl	r2, r1, r2
+	.loc 1 20 16
+	mvns	r2, r2
+	.loc 1 20 13
+	ands	r2, r2, r3
+	ldr	r3, [r7, #12]
+	str	r2, [r3, #36]
+	.loc 1 21 6
+	ldr	r3, [r7, #12]
+	ldr	r3, [r3, #36]
+	.loc 1 21 20
+	ldrb	r2, [r7, #5]	@ zero_extendqisi2
+	and	r1, r2, #15
+	.loc 1 21 37
+	ldr	r2, [r7, #8]
+	lsls	r2, r2, #2
+	.loc 1 21 30
+	lsl	r2, r1, r2
+	.loc 1 21 13
+	orrs	r2, r2, r3
+	ldr	r3, [r7, #12]
+	str	r2, [r3, #36]
+.L5:
+	.loc 1 23 1
 	nop
 	adds	r7, r7, #20
 	.cfi_def_cfa_offset 4
@@ -174,6 +224,79 @@ gpio_write:
 	bx	lr
 	.cfi_endproc
 .LFE1:
+	.size	gpio_set_af, .-gpio_set_af
+	.section	.text.gpio_write,"ax",%progbits
+	.align	1
+	.global	gpio_write
+	.syntax unified
+	.thumb
+	.thumb_func
+	.type	gpio_write, %function
+gpio_write:
+.LFB2:
+	.loc 1 25 40
+	.cfi_startproc
+	@ args = 0, pretend = 0, frame = 16
+	@ frame_needed = 1, uses_anonymous_args = 0
+	@ link register save eliminated.
+	push	{r7}
+	.cfi_def_cfa_offset 4
+	.cfi_offset 7, -4
+	sub	sp, sp, #20
+	.cfi_def_cfa_offset 24
+	add	r7, sp, #0
+	.cfi_def_cfa_register 7
+	mov	r3, r0
+	mov	r2, r1
+	strh	r3, [r7, #6]	@ movhi
+	mov	r3, r2
+	strb	r3, [r7, #5]
+	.loc 1 26 83
+	ldrh	r3, [r7, #6]
+	lsrs	r3, r3, #8
+	uxth	r3, r3
+	.loc 1 26 38
+	add	r3, r3, #1048576
+	adds	r3, r3, #128
+	lsls	r3, r3, #10
+	.loc 1 26 16
+	str	r3, [r7, #12]
+	.loc 1 27 32
+	ldrh	r3, [r7, #6]
+	and	r3, r3, #15
+	.loc 1 27 24
+	movs	r2, #3
+	lsls	r2, r2, r3
+	.loc 1 27 55
+	ldrb	r3, [r7, #5]	@ zero_extendqisi2
+	cmp	r3, #0
+	beq	.L7
+	.loc 1 27 55 is_stmt 0 discriminator 1
+	movs	r3, #0
+	b	.L8
+.L7:
+	.loc 1 27 55 discriminator 2
+	movs	r3, #16
+.L8:
+	.loc 1 27 43 is_stmt 1 discriminator 4
+	lsl	r3, r2, r3
+	mov	r2, r3
+	.loc 1 27 14 discriminator 4
+	ldr	r3, [r7, #12]
+	str	r2, [r3, #24]
+	.loc 1 28 1 discriminator 4
+	nop
+	adds	r7, r7, #20
+	.cfi_def_cfa_offset 4
+	mov	sp, r7
+	.cfi_def_cfa_register 13
+	@ sp needed
+	ldr	r7, [sp], #4
+	.cfi_restore 7
+	.cfi_def_cfa_offset 0
+	bx	lr
+	.cfi_endproc
+.LFE2:
 	.size	gpio_write, .-gpio_write
 	.text
 .Letext0:
@@ -182,16 +305,16 @@ gpio_write:
 	.file 4 "src/gpio.h"
 	.section	.debug_info,"",%progbits
 .Ldebug_info0:
-	.4byte	0x201
+	.4byte	0x25e
 	.2byte	0x5
 	.byte	0x1
 	.byte	0x4
 	.4byte	.Ldebug_abbrev0
-	.uleb128 0x8
-	.4byte	.LASF894
+	.uleb128 0xa
+	.4byte	.LASF898
 	.byte	0x1d
-	.4byte	.LASF895
-	.4byte	.LASF896
+	.4byte	.LASF899
+	.4byte	.LASF900
 	.4byte	.LLRL0
 	.4byte	0
 	.4byte	.Ldebug_line0
@@ -200,6 +323,12 @@ gpio_write:
 	.byte	0x1
 	.byte	0x6
 	.4byte	.LASF863
+	.uleb128 0x2
+	.4byte	.LASF866
+	.byte	0x2
+	.byte	0x2b
+	.byte	0x17
+	.4byte	0x3d
 	.uleb128 0x1
 	.byte	0x1
 	.byte	0x8
@@ -208,187 +337,191 @@ gpio_write:
 	.byte	0x2
 	.byte	0x5
 	.4byte	.LASF865
-	.uleb128 0x3
-	.4byte	.LASF868
+	.uleb128 0x2
+	.4byte	.LASF867
 	.byte	0x2
 	.byte	0x39
 	.byte	0x1c
-	.4byte	0x4b
+	.4byte	0x57
 	.uleb128 0x1
 	.byte	0x2
 	.byte	0x7
-	.4byte	.LASF866
+	.4byte	.LASF868
 	.uleb128 0x1
 	.byte	0x4
 	.byte	0x5
-	.4byte	.LASF867
-	.uleb128 0x3
 	.4byte	.LASF869
+	.uleb128 0x2
+	.4byte	.LASF870
 	.byte	0x2
 	.byte	0x4f
 	.byte	0x1b
-	.4byte	0x65
+	.4byte	0x71
 	.uleb128 0x1
 	.byte	0x4
 	.byte	0x7
-	.4byte	.LASF870
-	.uleb128 0x1
-	.byte	0x8
-	.byte	0x5
 	.4byte	.LASF871
 	.uleb128 0x1
 	.byte	0x8
-	.byte	0x7
+	.byte	0x5
 	.4byte	.LASF872
-	.uleb128 0x9
+	.uleb128 0x1
+	.byte	0x8
+	.byte	0x7
+	.4byte	.LASF873
+	.uleb128 0xb
 	.byte	0x4
 	.byte	0x5
 	.ascii	"int\000"
-	.uleb128 0x3
-	.4byte	.LASF873
+	.uleb128 0x2
+	.4byte	.LASF874
 	.byte	0x2
 	.byte	0xe8
 	.byte	0x16
-	.4byte	0x8d
+	.4byte	0x99
 	.uleb128 0x1
 	.byte	0x4
 	.byte	0x7
-	.4byte	.LASF874
-	.uleb128 0x3
 	.4byte	.LASF875
+	.uleb128 0x2
+	.4byte	.LASF876
+	.byte	0x3
+	.byte	0x18
+	.byte	0x13
+	.4byte	0x31
+	.uleb128 0x2
+	.4byte	.LASF877
 	.byte	0x3
 	.byte	0x24
 	.byte	0x14
-	.4byte	0x3f
-	.uleb128 0x3
-	.4byte	.LASF876
+	.4byte	0x4b
+	.uleb128 0x2
+	.4byte	.LASF878
 	.byte	0x3
 	.byte	0x30
 	.byte	0x14
-	.4byte	0x59
-	.uleb128 0xa
-	.4byte	0xa0
-	.uleb128 0x3
-	.4byte	.LASF877
+	.4byte	0x65
+	.uleb128 0xc
+	.4byte	0xb8
+	.uleb128 0x2
+	.4byte	.LASF879
 	.byte	0x3
 	.byte	0x52
 	.byte	0x15
-	.4byte	0x81
-	.uleb128 0xb
-	.4byte	.LASF893
+	.4byte	0x8d
+	.uleb128 0xd
+	.4byte	.LASF896
 	.byte	0x28
 	.byte	0x4
 	.byte	0x7
 	.byte	0x8
-	.4byte	0x139
-	.uleb128 0x2
-	.4byte	.LASF878
-	.byte	0x8
-	.4byte	0xac
-	.byte	0
-	.uleb128 0x2
-	.4byte	.LASF879
-	.byte	0x9
-	.4byte	0xac
-	.byte	0x4
-	.uleb128 0x2
+	.4byte	0x151
+	.uleb128 0x3
 	.4byte	.LASF880
-	.byte	0xa
-	.4byte	0xac
 	.byte	0x8
-	.uleb128 0x2
+	.4byte	0xc4
+	.byte	0
+	.uleb128 0x3
 	.4byte	.LASF881
+	.byte	0x9
+	.4byte	0xc4
+	.byte	0x4
+	.uleb128 0x3
+	.4byte	.LASF882
+	.byte	0xa
+	.4byte	0xc4
+	.byte	0x8
+	.uleb128 0x3
+	.4byte	.LASF883
 	.byte	0xb
-	.4byte	0xac
+	.4byte	0xc4
 	.byte	0xc
-	.uleb128 0x6
+	.uleb128 0x7
 	.ascii	"IDR\000"
 	.byte	0xc
-	.4byte	0xac
+	.4byte	0xc4
 	.byte	0x10
-	.uleb128 0x6
+	.uleb128 0x7
 	.ascii	"ODR\000"
 	.byte	0xd
-	.4byte	0xac
+	.4byte	0xc4
 	.byte	0x14
-	.uleb128 0x2
-	.4byte	.LASF882
-	.byte	0xe
-	.4byte	0xac
-	.byte	0x18
-	.uleb128 0x2
-	.4byte	.LASF883
-	.byte	0xf
-	.4byte	0xac
-	.byte	0x1c
-	.uleb128 0x2
+	.uleb128 0x3
 	.4byte	.LASF884
-	.byte	0x10
-	.4byte	0xac
-	.byte	0x20
-	.uleb128 0x2
+	.byte	0xe
+	.4byte	0xc4
+	.byte	0x18
+	.uleb128 0x3
 	.4byte	.LASF885
+	.byte	0xf
+	.4byte	0xc4
+	.byte	0x1c
+	.uleb128 0x3
+	.4byte	.LASF886
+	.byte	0x10
+	.4byte	0xc4
+	.byte	0x20
+	.uleb128 0x3
+	.4byte	.LASF887
 	.byte	0x11
-	.4byte	0xac
+	.4byte	0xc4
 	.byte	0x24
 	.byte	0
-	.uleb128 0xc
+	.uleb128 0xe
 	.byte	0x7
 	.byte	0x1
-	.4byte	0x31
+	.4byte	0x3d
 	.byte	0x4
 	.byte	0x21
 	.byte	0xe
-	.4byte	0x160
-	.uleb128 0x4
-	.4byte	.LASF886
-	.byte	0
-	.uleb128 0x4
-	.4byte	.LASF887
-	.byte	0x1
-	.uleb128 0x4
+	.4byte	0x178
+	.uleb128 0x5
 	.4byte	.LASF888
-	.byte	0x2
-	.uleb128 0x4
+	.byte	0
+	.uleb128 0x5
 	.4byte	.LASF889
+	.byte	0x1
+	.uleb128 0x5
+	.4byte	.LASF890
+	.byte	0x2
+	.uleb128 0x5
+	.4byte	.LASF891
 	.byte	0x3
 	.byte	0
-	.uleb128 0x3
-	.4byte	.LASF890
+	.uleb128 0x2
+	.4byte	.LASF892
 	.byte	0x4
 	.byte	0x26
 	.byte	0x3
-	.4byte	0x139
-	.uleb128 0xd
-	.4byte	.LASF897
-	.byte	0x1
-	.byte	0xd
-	.byte	0x6
-	.4byte	.LFB1
-	.4byte	.LFE1-.LFB1
+	.4byte	0x151
+	.uleb128 0x8
+	.4byte	.LASF894
+	.byte	0x19
+	.4byte	.LFB2
+	.4byte	.LFE2-.LFB2
 	.uleb128 0x1
 	.byte	0x9c
-	.4byte	0x1ac
-	.uleb128 0x5
+	.4byte	0x1c2
+	.uleb128 0x4
 	.ascii	"pin\000"
-	.byte	0xd
+	.byte	0x19
 	.byte	0x1a
-	.4byte	0x94
+	.4byte	0xac
 	.uleb128 0x2
 	.byte	0x91
 	.sleb128 -18
-	.uleb128 0x5
+	.uleb128 0x4
 	.ascii	"val\000"
-	.byte	0xd
+	.byte	0x19
 	.byte	0x23
-	.4byte	0x1ac
+	.4byte	0x1c2
 	.uleb128 0x2
 	.byte	0x91
 	.sleb128 -19
-	.uleb128 0x7
-	.4byte	.LASF893
-	.byte	0xe
-	.4byte	0x1b3
+	.uleb128 0x6
+	.4byte	.LASF896
+	.byte	0x1a
+	.4byte	0x1c9
 	.uleb128 0x2
 	.byte	0x91
 	.sleb128 -12
@@ -396,12 +529,51 @@ gpio_write:
 	.uleb128 0x1
 	.byte	0x1
 	.byte	0x2
-	.4byte	.LASF891
-	.uleb128 0xe
-	.byte	0x4
-	.4byte	0xbd
+	.4byte	.LASF893
 	.uleb128 0xf
-	.4byte	.LASF898
+	.byte	0x4
+	.4byte	0xd5
+	.uleb128 0x8
+	.4byte	.LASF895
+	.byte	0xd
+	.4byte	.LFB1
+	.4byte	.LFE1-.LFB1
+	.uleb128 0x1
+	.byte	0x9c
+	.4byte	0x218
+	.uleb128 0x4
+	.ascii	"pin\000"
+	.byte	0xd
+	.byte	0x1b
+	.4byte	0xac
+	.uleb128 0x2
+	.byte	0x91
+	.sleb128 -18
+	.uleb128 0x4
+	.ascii	"af\000"
+	.byte	0xd
+	.byte	0x28
+	.4byte	0xa0
+	.uleb128 0x2
+	.byte	0x91
+	.sleb128 -19
+	.uleb128 0x6
+	.4byte	.LASF896
+	.byte	0xe
+	.4byte	0x1c9
+	.uleb128 0x2
+	.byte	0x91
+	.sleb128 -12
+	.uleb128 0x9
+	.ascii	"pn\000"
+	.byte	0xf
+	.4byte	0x86
+	.uleb128 0x2
+	.byte	0x91
+	.sleb128 -16
+	.byte	0
+	.uleb128 0x10
+	.4byte	.LASF901
 	.byte	0x1
 	.byte	0x6
 	.byte	0x6
@@ -409,36 +581,34 @@ gpio_write:
 	.4byte	.LFE0-.LFB0
 	.uleb128 0x1
 	.byte	0x9c
-	.uleb128 0x5
+	.uleb128 0x4
 	.ascii	"pin\000"
 	.byte	0x6
 	.byte	0x1d
-	.4byte	0x94
+	.4byte	0xac
 	.uleb128 0x2
 	.byte	0x91
 	.sleb128 -18
-	.uleb128 0x10
-	.4byte	.LASF892
+	.uleb128 0x11
+	.4byte	.LASF897
 	.byte	0x1
 	.byte	0x6
 	.byte	0x2c
-	.4byte	0x160
+	.4byte	0x178
 	.uleb128 0x2
 	.byte	0x91
 	.sleb128 -19
-	.uleb128 0x7
-	.4byte	.LASF893
+	.uleb128 0x6
+	.4byte	.LASF896
 	.byte	0x7
-	.4byte	0x1b3
+	.4byte	0x1c9
 	.uleb128 0x2
 	.byte	0x91
 	.sleb128 -12
-	.uleb128 0x11
+	.uleb128 0x9
 	.ascii	"pn\000"
-	.byte	0x1
 	.byte	0x8
-	.byte	0x7
-	.4byte	0x7a
+	.4byte	0x86
 	.uleb128 0x2
 	.byte	0x91
 	.sleb128 -16
@@ -458,6 +628,21 @@ gpio_write:
 	.byte	0
 	.byte	0
 	.uleb128 0x2
+	.uleb128 0x16
+	.byte	0
+	.uleb128 0x3
+	.uleb128 0xe
+	.uleb128 0x3a
+	.uleb128 0xb
+	.uleb128 0x3b
+	.uleb128 0xb
+	.uleb128 0x39
+	.uleb128 0xb
+	.uleb128 0x49
+	.uleb128 0x13
+	.byte	0
+	.byte	0
+	.uleb128 0x3
 	.uleb128 0xd
 	.byte	0
 	.uleb128 0x3
@@ -476,31 +661,7 @@ gpio_write:
 	.uleb128 0xb
 	.byte	0
 	.byte	0
-	.uleb128 0x3
-	.uleb128 0x16
-	.byte	0
-	.uleb128 0x3
-	.uleb128 0xe
-	.uleb128 0x3a
-	.uleb128 0xb
-	.uleb128 0x3b
-	.uleb128 0xb
-	.uleb128 0x39
-	.uleb128 0xb
-	.uleb128 0x49
-	.uleb128 0x13
-	.byte	0
-	.byte	0
 	.uleb128 0x4
-	.uleb128 0x28
-	.byte	0
-	.uleb128 0x3
-	.uleb128 0xe
-	.uleb128 0x1c
-	.uleb128 0xb
-	.byte	0
-	.byte	0
-	.uleb128 0x5
 	.uleb128 0x5
 	.byte	0
 	.uleb128 0x3
@@ -518,26 +679,16 @@ gpio_write:
 	.uleb128 0x18
 	.byte	0
 	.byte	0
-	.uleb128 0x6
-	.uleb128 0xd
+	.uleb128 0x5
+	.uleb128 0x28
 	.byte	0
 	.uleb128 0x3
-	.uleb128 0x8
-	.uleb128 0x3a
-	.uleb128 0x21
-	.sleb128 4
-	.uleb128 0x3b
-	.uleb128 0xb
-	.uleb128 0x39
-	.uleb128 0x21
-	.sleb128 21
-	.uleb128 0x49
-	.uleb128 0x13
-	.uleb128 0x38
+	.uleb128 0xe
+	.uleb128 0x1c
 	.uleb128 0xb
 	.byte	0
 	.byte	0
-	.uleb128 0x7
+	.uleb128 0x6
 	.uleb128 0x34
 	.byte	0
 	.uleb128 0x3
@@ -556,7 +707,74 @@ gpio_write:
 	.uleb128 0x18
 	.byte	0
 	.byte	0
+	.uleb128 0x7
+	.uleb128 0xd
+	.byte	0
+	.uleb128 0x3
 	.uleb128 0x8
+	.uleb128 0x3a
+	.uleb128 0x21
+	.sleb128 4
+	.uleb128 0x3b
+	.uleb128 0xb
+	.uleb128 0x39
+	.uleb128 0x21
+	.sleb128 21
+	.uleb128 0x49
+	.uleb128 0x13
+	.uleb128 0x38
+	.uleb128 0xb
+	.byte	0
+	.byte	0
+	.uleb128 0x8
+	.uleb128 0x2e
+	.byte	0x1
+	.uleb128 0x3f
+	.uleb128 0x19
+	.uleb128 0x3
+	.uleb128 0xe
+	.uleb128 0x3a
+	.uleb128 0x21
+	.sleb128 1
+	.uleb128 0x3b
+	.uleb128 0xb
+	.uleb128 0x39
+	.uleb128 0x21
+	.sleb128 6
+	.uleb128 0x27
+	.uleb128 0x19
+	.uleb128 0x11
+	.uleb128 0x1
+	.uleb128 0x12
+	.uleb128 0x6
+	.uleb128 0x40
+	.uleb128 0x18
+	.uleb128 0x7a
+	.uleb128 0x19
+	.uleb128 0x1
+	.uleb128 0x13
+	.byte	0
+	.byte	0
+	.uleb128 0x9
+	.uleb128 0x34
+	.byte	0
+	.uleb128 0x3
+	.uleb128 0x8
+	.uleb128 0x3a
+	.uleb128 0x21
+	.sleb128 1
+	.uleb128 0x3b
+	.uleb128 0xb
+	.uleb128 0x39
+	.uleb128 0x21
+	.sleb128 7
+	.uleb128 0x49
+	.uleb128 0x13
+	.uleb128 0x2
+	.uleb128 0x18
+	.byte	0
+	.byte	0
+	.uleb128 0xa
 	.uleb128 0x11
 	.byte	0x1
 	.uleb128 0x25
@@ -577,7 +795,7 @@ gpio_write:
 	.uleb128 0x17
 	.byte	0
 	.byte	0
-	.uleb128 0x9
+	.uleb128 0xb
 	.uleb128 0x24
 	.byte	0
 	.uleb128 0xb
@@ -588,14 +806,14 @@ gpio_write:
 	.uleb128 0x8
 	.byte	0
 	.byte	0
-	.uleb128 0xa
+	.uleb128 0xc
 	.uleb128 0x35
 	.byte	0
 	.uleb128 0x49
 	.uleb128 0x13
 	.byte	0
 	.byte	0
-	.uleb128 0xb
+	.uleb128 0xd
 	.uleb128 0x13
 	.byte	0x1
 	.uleb128 0x3
@@ -612,7 +830,7 @@ gpio_write:
 	.uleb128 0x13
 	.byte	0
 	.byte	0
-	.uleb128 0xc
+	.uleb128 0xe
 	.uleb128 0x4
 	.byte	0x1
 	.uleb128 0x3e
@@ -631,34 +849,7 @@ gpio_write:
 	.uleb128 0x13
 	.byte	0
 	.byte	0
-	.uleb128 0xd
-	.uleb128 0x2e
-	.byte	0x1
-	.uleb128 0x3f
-	.uleb128 0x19
-	.uleb128 0x3
-	.uleb128 0xe
-	.uleb128 0x3a
-	.uleb128 0xb
-	.uleb128 0x3b
-	.uleb128 0xb
-	.uleb128 0x39
-	.uleb128 0xb
-	.uleb128 0x27
-	.uleb128 0x19
-	.uleb128 0x11
-	.uleb128 0x1
-	.uleb128 0x12
-	.uleb128 0x6
-	.uleb128 0x40
-	.uleb128 0x18
-	.uleb128 0x7a
-	.uleb128 0x19
-	.uleb128 0x1
-	.uleb128 0x13
-	.byte	0
-	.byte	0
-	.uleb128 0xe
+	.uleb128 0xf
 	.uleb128 0xf
 	.byte	0
 	.uleb128 0xb
@@ -667,7 +858,7 @@ gpio_write:
 	.uleb128 0x13
 	.byte	0
 	.byte	0
-	.uleb128 0xf
+	.uleb128 0x10
 	.uleb128 0x2e
 	.byte	0x1
 	.uleb128 0x3f
@@ -692,7 +883,7 @@ gpio_write:
 	.uleb128 0x19
 	.byte	0
 	.byte	0
-	.uleb128 0x10
+	.uleb128 0x11
 	.uleb128 0x5
 	.byte	0
 	.uleb128 0x3
@@ -709,26 +900,9 @@ gpio_write:
 	.uleb128 0x18
 	.byte	0
 	.byte	0
-	.uleb128 0x11
-	.uleb128 0x34
-	.byte	0
-	.uleb128 0x3
-	.uleb128 0x8
-	.uleb128 0x3a
-	.uleb128 0xb
-	.uleb128 0x3b
-	.uleb128 0xb
-	.uleb128 0x39
-	.uleb128 0xb
-	.uleb128 0x49
-	.uleb128 0x13
-	.uleb128 0x2
-	.uleb128 0x18
-	.byte	0
-	.byte	0
 	.byte	0
 	.section	.debug_aranges,"",%progbits
-	.4byte	0x24
+	.4byte	0x2c
 	.2byte	0x2
 	.4byte	.Ldebug_info0
 	.byte	0x4
@@ -739,6 +913,8 @@ gpio_write:
 	.4byte	.LFE0-.LFB0
 	.4byte	.LFB1
 	.4byte	.LFE1-.LFB1
+	.4byte	.LFB2
+	.4byte	.LFE2-.LFB2
 	.4byte	0
 	.4byte	0
 	.section	.debug_rnglists,"",%progbits
@@ -756,6 +932,9 @@ gpio_write:
 	.byte	0x7
 	.4byte	.LFB1
 	.uleb128 .LFE1-.LFB1
+	.byte	0x7
+	.4byte	.LFB2
+	.uleb128 .LFE2-.LFB2
 	.byte	0
 .Ldebug_ranges3:
 	.section	.debug_macro,"",%progbits
@@ -3587,8 +3766,8 @@ gpio_write:
 	.ascii	"__SCN32FAST(x) __FAST32 __STRINGIFY(x)\000"
 .LASF318:
 	.ascii	"__LLACCUM_MIN__ (-0X1P31LLK-0X1P31LLK)\000"
-.LASF381:
-	.ascii	"__GCC_DESTRUCTIVE_SIZE 64\000"
+.LASF338:
+	.ascii	"__UHQ_FBIT__ 16\000"
 .LASF310:
 	.ascii	"__LACCUM_EPSILON__ 0x1P-31LK\000"
 .LASF809:
@@ -3597,7 +3776,7 @@ gpio_write:
 	.ascii	"__PTRDIFF_MAX__ 0x7fffffff\000"
 .LASF541:
 	.ascii	"_LONG_DOUBLE long double\000"
-.LASF893:
+.LASF896:
 	.ascii	"gpio\000"
 .LASF591:
 	.ascii	"INT_LEAST8_MIN (-__INT_LEAST8_MAX__ - 1)\000"
@@ -3605,7 +3784,7 @@ gpio_write:
 	.ascii	"_UINT32_T_DECLARED \000"
 .LASF90:
 	.ascii	"__INTMAX_MAX__ 0x7fffffffffffffffLL\000"
-.LASF888:
+.LASF890:
 	.ascii	"GPIO_MODE_AF\000"
 .LASF335:
 	.ascii	"__TQ_IBIT__ 0\000"
@@ -3719,7 +3898,7 @@ gpio_write:
 	.ascii	"__need_wchar_t\000"
 .LASF199:
 	.ascii	"__FLT32_MIN_EXP__ (-125)\000"
-.LASF894:
+.LASF898:
 	.ascii	"GNU C2X 12.3.1 20230626 -mcpu=cortex-m4 -mthumb -mf"
 	.ascii	"loat-abi=hard -mfpu=fpv4-sp-d16 -march=armv7e-m+fp "
 	.ascii	"-g3 -ggdb -O0 -std=c2x -ffunction-sections -fdata-s"
@@ -3788,8 +3967,8 @@ gpio_write:
 	.ascii	"__LACCUM_IBIT__ 32\000"
 .LASF592:
 	.ascii	"INT_LEAST8_MAX (__INT_LEAST8_MAX__)\000"
-.LASF559:
-	.ascii	"__EXP\000"
+.LASF866:
+	.ascii	"__uint8_t\000"
 .LASF81:
 	.ascii	"__SCHAR_WIDTH__ 8\000"
 .LASF455:
@@ -3838,9 +4017,7 @@ gpio_write:
 	.ascii	"__ACCUM_FBIT__ 15\000"
 .LASF791:
 	.ascii	"PRId64 __PRI64(d)\000"
-.LASF302:
-	.ascii	"__UACCUM_IBIT__ 16\000"
-.LASF867:
+.LASF869:
 	.ascii	"long int\000"
 .LASF818:
 	.ascii	"PRIXFAST64 __PRI64FAST(X)\000"
@@ -3936,7 +4113,7 @@ gpio_write:
 	.ascii	"PRIoLEAST16 __PRI16LEAST(o)\000"
 .LASF458:
 	.ascii	"__NEWLIB__ 4\000"
-.LASF886:
+.LASF888:
 	.ascii	"GPIO_MODE_INPUT\000"
 .LASF720:
 	.ascii	"SCNi16 __SCN16(i)\000"
@@ -3950,15 +4127,17 @@ gpio_write:
 	.ascii	"signed char\000"
 .LASF805:
 	.ascii	"PRIuLEAST64 __PRI64LEAST(u)\000"
+.LASF876:
+	.ascii	"uint8_t\000"
 .LASF704:
 	.ascii	"SCNoFAST8 __SCN8FAST(o)\000"
 .LASF625:
 	.ascii	"INTMAX_MIN (-INTMAX_MAX - 1)\000"
 .LASF431:
 	.ascii	"__ARM_FEATURE_FMA 1\000"
-.LASF364:
-	.ascii	"__GNUC_STDC_INLINE__ 1\000"
-.LASF890:
+.LASF466:
+	.ascii	"_HAVE_LONG_DOUBLE 1\000"
+.LASF892:
 	.ascii	"GPIO_MODE\000"
 .LASF256:
 	.ascii	"__FRACT_FBIT__ 15\000"
@@ -4024,19 +4203,17 @@ gpio_write:
 	.ascii	"__PRI16LEAST(x) __LEAST16 __STRINGIFY(x)\000"
 .LASF494:
 	.ascii	"__POSIX_VISIBLE 0\000"
-.LASF466:
-	.ascii	"_HAVE_LONG_DOUBLE 1\000"
 .LASF584:
 	.ascii	"__int_fast64_t_defined 1\000"
 .LASF837:
 	.ascii	"__PRIPTR(x) __STRINGIFY(x)\000"
-.LASF875:
+.LASF877:
 	.ascii	"uint16_t\000"
 .LASF417:
 	.ascii	"__thumb2__ 1\000"
 .LASF321:
 	.ascii	"__ULLACCUM_FBIT__ 32\000"
-.LASF891:
+.LASF893:
 	.ascii	"_Bool\000"
 .LASF366:
 	.ascii	"__STRICT_ANSI__ 1\000"
@@ -4056,7 +4233,7 @@ gpio_write:
 	.ascii	"__WCHAR_TYPE__ unsigned int\000"
 .LASF859:
 	.ascii	"PORT(port) (((port) - 'A') << 8)\000"
-.LASF887:
+.LASF889:
 	.ascii	"GPIO_MODE_OUTPUT\000"
 .LASF357:
 	.ascii	"__USA_IBIT__ 16\000"
@@ -4094,7 +4271,7 @@ gpio_write:
 	.ascii	"__SCN64(x) __INT64 __STRINGIFY(x)\000"
 .LASF646:
 	.ascii	"_GCC_WRAP_STDINT_H \000"
-.LASF868:
+.LASF867:
 	.ascii	"__uint16_t\000"
 .LASF224:
 	.ascii	"__FLT64_EPSILON__ 2.2204460492503131e-16F64\000"
@@ -4304,7 +4481,7 @@ gpio_write:
 	.ascii	"___int8_t_defined 1\000"
 .LASF248:
 	.ascii	"__SFRACT_MIN__ (-0.5HR-0.5HR)\000"
-.LASF870:
+.LASF871:
 	.ascii	"long unsigned int\000"
 .LASF349:
 	.ascii	"__SA_IBIT__ 16\000"
@@ -4320,7 +4497,7 @@ gpio_write:
 	.ascii	"__ARM_FP16_FORMAT_IEEE\000"
 .LASF48:
 	.ascii	"__UINT16_TYPE__ short unsigned int\000"
-.LASF897:
+.LASF894:
 	.ascii	"gpio_write\000"
 .LASF569:
 	.ascii	"__int32_t_defined 1\000"
@@ -4364,7 +4541,7 @@ gpio_write:
 	.ascii	"SCNx8 __SCN8(x)\000"
 .LASF208:
 	.ascii	"__FLT32_DENORM_MIN__ 1.4012984643248171e-45F32\000"
-.LASF898:
+.LASF901:
 	.ascii	"gpio_set_mode\000"
 .LASF125:
 	.ascii	"__UINT64_C(c) c ## ULL\000"
@@ -4384,7 +4561,7 @@ gpio_write:
 	.ascii	"__GCC_ATOMIC_CHAR16_T_LOCK_FREE 2\000"
 .LASF789:
 	.ascii	"__PRI64FAST(x) __FAST64 __STRINGIFY(x)\000"
-.LASF877:
+.LASF879:
 	.ascii	"uintptr_t\000"
 .LASF168:
 	.ascii	"__DBL_MAX_EXP__ 1024\000"
@@ -4432,7 +4609,7 @@ gpio_write:
 	.ascii	"PRIX32 __PRI32(X)\000"
 .LASF773:
 	.ascii	"SCNxLEAST32 __SCN32LEAST(x)\000"
-.LASF880:
+.LASF882:
 	.ascii	"OSPEEDR\000"
 .LASF711:
 	.ascii	"__SCN16LEAST(x) __LEAST16 __STRINGIFY(x)\000"
@@ -4462,7 +4639,7 @@ gpio_write:
 	.ascii	"__ULACCUM_MIN__ 0.0ULK\000"
 .LASF461:
 	.ascii	"_ATEXIT_DYNAMIC_ALLOC 1\000"
-.LASF869:
+.LASF870:
 	.ascii	"__uint32_t\000"
 .LASF188:
 	.ascii	"__LDBL_MAX__ 1.7976931348623157e+308L\000"
@@ -4472,7 +4649,7 @@ gpio_write:
 	.ascii	"__FLT_RADIX__ 2\000"
 .LASF454:
 	.ascii	"_INTTYPES_H \000"
-.LASF871:
+.LASF872:
 	.ascii	"long long int\000"
 .LASF401:
 	.ascii	"__ARM_FEATURE_CMSE\000"
@@ -4492,6 +4669,8 @@ gpio_write:
 	.ascii	"_NEWLIB_VERSION \"4.3.0\"\000"
 .LASF137:
 	.ascii	"__UINT_FAST64_MAX__ 0xffffffffffffffffULL\000"
+.LASF722:
+	.ascii	"SCNu16 __SCN16(u)\000"
 .LASF423:
 	.ascii	"__ARM_FP\000"
 .LASF347:
@@ -4577,7 +4756,7 @@ gpio_write:
 	.ascii	"\000"
 .LASF582:
 	.ascii	"__int_fast16_t_defined 1\000"
-.LASF878:
+.LASF880:
 	.ascii	"MODER\000"
 .LASF482:
 	.ascii	"__FLOAT_TYPE float\000"
@@ -4588,9 +4767,9 @@ gpio_write:
 	.ascii	"L)\000"
 .LASF607:
 	.ascii	"INT64_MAX (__INT64_MAX__)\000"
-.LASF874:
+.LASF875:
 	.ascii	"unsigned int\000"
-.LASF873:
+.LASF874:
 	.ascii	"__uintptr_t\000"
 .LASF459:
 	.ascii	"__NEWLIB_MINOR__ 3\000"
@@ -4616,8 +4795,6 @@ gpio_write:
 	.ascii	"_FVWRITE_IN_STREAMIO 1\000"
 .LASF662:
 	.ascii	"_WCHAR_T_DECLARED \000"
-.LASF361:
-	.ascii	"__UTA_IBIT__ 64\000"
 .LASF24:
 	.ascii	"__CHAR_BIT__ 8\000"
 .LASF143:
@@ -4628,6 +4805,8 @@ gpio_write:
 	.ascii	"PRIdLEAST8 __PRI8LEAST(d)\000"
 .LASF70:
 	.ascii	"__SCHAR_MAX__ 0x7f\000"
+.LASF559:
+	.ascii	"__EXP\000"
 .LASF127:
 	.ascii	"__INT_FAST8_WIDTH__ 32\000"
 .LASF2:
@@ -4644,6 +4823,8 @@ gpio_write:
 	.ascii	"__LFRACT_MAX__ 0X7FFFFFFFP-31LR\000"
 .LASF389:
 	.ascii	"__SIZEOF_PTRDIFF_T__ 4\000"
+.LASF270:
+	.ascii	"__LFRACT_EPSILON__ 0x1P-31LR\000"
 .LASF649:
 	.ascii	"__WCHAR_T__ \000"
 .LASF555:
@@ -4662,6 +4843,8 @@ gpio_write:
 	.ascii	"__ARM_FEATURE_COPROC 15\000"
 .LASF483:
 	.ascii	"__OBSOLETE_MATH_DEFAULT 1\000"
+.LASF895:
+	.ascii	"gpio_set_af\000"
 .LASF82:
 	.ascii	"__SHRT_WIDTH__ 16\000"
 .LASF472:
@@ -4682,8 +4865,8 @@ gpio_write:
 	.ascii	"__ATFILE_VISIBLE 0\000"
 .LASF372:
 	.ascii	"__GCC_ATOMIC_CHAR_LOCK_FREE 2\000"
-.LASF270:
-	.ascii	"__LFRACT_EPSILON__ 0x1P-31LR\000"
+.LASF695:
+	.ascii	"SCNxLEAST8 __SCN8LEAST(x)\000"
 .LASF808:
 	.ascii	"SCNdLEAST64 __SCN64LEAST(d)\000"
 .LASF538:
@@ -4808,7 +4991,7 @@ gpio_write:
 	.ascii	"__ORDER_LITTLE_ENDIAN__ 1234\000"
 .LASF155:
 	.ascii	"__FLT_NORM_MAX__ 3.4028234663852886e+38F\000"
-.LASF872:
+.LASF873:
 	.ascii	"long long unsigned int\000"
 .LASF611:
 	.ascii	"UINT_LEAST64_MAX (__UINT_LEAST64_MAX__)\000"
@@ -4822,8 +5005,6 @@ gpio_write:
 	.ascii	"__SHRT_MAX__ 0x7fff\000"
 .LASF196:
 	.ascii	"__LDBL_IS_IEC_60559__ 2\000"
-.LASF695:
-	.ascii	"SCNxLEAST8 __SCN8LEAST(x)\000"
 .LASF35:
 	.ascii	"__PTRDIFF_TYPE__ int\000"
 .LASF670:
@@ -4886,11 +5067,11 @@ gpio_write:
 	.ascii	"SCNdFAST8 __SCN8FAST(d)\000"
 .LASF576:
 	.ascii	"_UINTPTR_T_DECLARED \000"
-.LASF885:
+.LASF887:
 	.ascii	"AFRH\000"
 .LASF314:
 	.ascii	"__ULACCUM_MAX__ 0XFFFFFFFFFFFFFFFFP-32ULK\000"
-.LASF884:
+.LASF886:
 	.ascii	"AFRL\000"
 .LASF273:
 	.ascii	"__ULFRACT_MIN__ 0.0ULR\000"
@@ -4904,7 +5085,7 @@ gpio_write:
 	.ascii	"__INT32_TYPE__ long int\000"
 .LASF118:
 	.ascii	"__UINT_LEAST8_MAX__ 0xff\000"
-.LASF883:
+.LASF885:
 	.ascii	"LCKR\000"
 .LASF520:
 	.ascii	"__int20__ +2\000"
@@ -4934,6 +5115,8 @@ gpio_write:
 	.ascii	"__ARM_EABI__ 1\000"
 .LASF465:
 	.ascii	"_HAVE_INITFINI_ARRAY 1\000"
+.LASF302:
+	.ascii	"__UACCUM_IBIT__ 16\000"
 .LASF732:
 	.ascii	"SCNoLEAST16 __SCN16LEAST(o)\000"
 .LASF473:
@@ -4952,7 +5135,7 @@ gpio_write:
 	.ascii	"__QQ_IBIT__ 0\000"
 .LASF763:
 	.ascii	"PRIdLEAST32 __PRI32LEAST(d)\000"
-.LASF879:
+.LASF881:
 	.ascii	"OTYPER\000"
 .LASF811:
 	.ascii	"SCNuLEAST64 __SCN64LEAST(u)\000"
@@ -4972,7 +5155,7 @@ gpio_write:
 	.ascii	"__GNUC_MINOR__ 3\000"
 .LASF57:
 	.ascii	"__UINT_LEAST32_TYPE__ long unsigned int\000"
-.LASF895:
+.LASF899:
 	.ascii	"src/gpio.c\000"
 .LASF405:
 	.ascii	"__ARM_FEATURE_NUMERIC_MAXMIN\000"
@@ -5046,17 +5229,17 @@ gpio_write:
 	.ascii	"__ACCUM_IBIT__ 16\000"
 .LASF509:
 	.ascii	"unsigned\000"
-.LASF881:
+.LASF381:
+	.ascii	"__GCC_DESTRUCTIVE_SIZE 64\000"
+.LASF883:
 	.ascii	"PUPDR\000"
 .LASF835:
 	.ascii	"SCNuMAX __SCNMAX(u)\000"
 .LASF121:
 	.ascii	"__UINT16_C(c) c\000"
-.LASF542:
-	.ascii	"_ATTRIBUTE(attrs) __attribute__ (attrs)\000"
 .LASF359:
 	.ascii	"__UDA_IBIT__ 32\000"
-.LASF892:
+.LASF897:
 	.ascii	"mode\000"
 .LASF586:
 	.ascii	"INTPTR_MAX (__INTPTR_MAX__)\000"
@@ -5066,11 +5249,11 @@ gpio_write:
 	.ascii	"INT64_MIN (-__INT64_MAX__ - 1)\000"
 .LASF9:
 	.ascii	"__ATOMIC_RELAXED 0\000"
-.LASF338:
-	.ascii	"__UHQ_FBIT__ 16\000"
+.LASF542:
+	.ascii	"_ATTRIBUTE(attrs) __attribute__ (attrs)\000"
 .LASF443:
 	.ascii	"__ARM_FEATURE_COPROC\000"
-.LASF889:
+.LASF891:
 	.ascii	"GPIO_MODE_ANALOG\000"
 .LASF177:
 	.ascii	"__DBL_HAS_INFINITY__ 1\000"
@@ -5108,7 +5291,7 @@ gpio_write:
 	.ascii	"__FAST8 \000"
 .LASF496:
 	.ascii	"__XSI_VISIBLE 0\000"
-.LASF882:
+.LASF884:
 	.ascii	"BSRR\000"
 .LASF794:
 	.ascii	"PRIu64 __PRI64(u)\000"
@@ -5120,8 +5303,8 @@ gpio_write:
 	.ascii	"PRIxMAX __PRIMAX(x)\000"
 .LASF487:
 	.ascii	"__GNUC_PREREQ__(ma,mi) __GNUC_PREREQ(ma, mi)\000"
-.LASF722:
-	.ascii	"SCNu16 __SCN16(u)\000"
+.LASF361:
+	.ascii	"__UTA_IBIT__ 64\000"
 .LASF322:
 	.ascii	"__ULLACCUM_IBIT__ 32\000"
 .LASF396:
@@ -5196,7 +5379,7 @@ gpio_write:
 	.ascii	"PRIx32 __PRI32(x)\000"
 .LASF278:
 	.ascii	"__LLFRACT_MIN__ (-0.5LLR-0.5LLR)\000"
-.LASF876:
+.LASF878:
 	.ascii	"uint32_t\000"
 .LASF689:
 	.ascii	"PRIxLEAST8 __PRI8LEAST(x)\000"
@@ -5220,6 +5403,8 @@ gpio_write:
 	.ascii	"SCNiFAST32 __SCN32FAST(i)\000"
 .LASF355:
 	.ascii	"__UHA_IBIT__ 8\000"
+.LASF364:
+	.ascii	"__GNUC_STDC_INLINE__ 1\000"
 .LASF300:
 	.ascii	"__ACCUM_EPSILON__ 0x1P-15K\000"
 .LASF315:
@@ -5250,7 +5435,7 @@ gpio_write:
 	.ascii	"PRIXLEAST32 __PRI32LEAST(X)\000"
 .LASF171:
 	.ascii	"__DBL_MAX__ ((double)1.7976931348623157e+308L)\000"
-.LASF866:
+.LASF868:
 	.ascii	"short unsigned int\000"
 .LASF276:
 	.ascii	"__LLFRACT_FBIT__ 63\000"
@@ -5298,7 +5483,7 @@ gpio_write:
 	.ascii	"__SCN64LEAST(x) __LEAST64 __STRINGIFY(x)\000"
 .LASF280:
 	.ascii	"__LLFRACT_EPSILON__ 0x1P-63LLR\000"
-.LASF896:
+.LASF900:
 	.ascii	"/home/alex/code/own/stm32-falling-sand\000"
 .LASF249:
 	.ascii	"__SFRACT_MAX__ 0X7FP-7HR\000"
diff --git a/build/gpio.i b/build/gpio.i
index bd007eb..cb23541 100644
--- a/build/gpio.i
+++ b/build/gpio.i
@@ -2020,10 +2020,11 @@ typedef enum {
 } GPIO_MODE;
 
 void gpio_set_mode(uint16_t pin, GPIO_MODE mode);
+void gpio_set_af(uint16_t pin, uint8_t af);
 void gpio_write(uint16_t pin, 
-# 41 "src/gpio.h" 3 4
+# 42 "src/gpio.h" 3 4
                              _Bool 
-# 41 "src/gpio.h"
+# 42 "src/gpio.h"
                                   val);
 # 5 "src/gpio.c" 2
 
@@ -2034,10 +2035,22 @@ void gpio_set_mode(uint16_t pin, GPIO_MODE mode) {
   gpio->MODER |= (mode & 0b11) << (pn * 2);
 }
 
+void gpio_set_af(uint16_t pin, uint8_t af) {
+  struct gpio *gpio = ((struct gpio*)(uintptr_t)((0x40020000U) + ((0x400U) * (pin >> 8))));
+  int pn = (pin & 0b1111);
+  if (pn < 8) {
+ gpio->AFRL &= ~(0b1111 << (pn * 4));
+ gpio->AFRL |= (af & 0b1111) << (pn * 4);
+  } else {
+ gpio->AFRH &= ~(0b1111 << (pn * 4));
+ gpio->AFRH |= (af & 0b1111) << (pn * 4);
+  }
+}
+
 void gpio_write(uint16_t pin, 
-# 13 "src/gpio.c" 3 4
+# 25 "src/gpio.c" 3 4
                              _Bool 
-# 13 "src/gpio.c"
+# 25 "src/gpio.c"
                                   val) {
   struct gpio *gpio = ((struct gpio*)(uintptr_t)((0x40020000U) + ((0x400U) * (pin >> 8))));
   gpio->BSRR = (0b0011 << (pin & 0b1111)) << (val ? 0 : 16);
diff --git a/build/gpio.o b/build/gpio.o
index 59a40c3..849a43d 100644
Binary files a/build/gpio.o and b/build/gpio.o differ
diff --git a/build/main.S b/build/main.S
index 72ecb9d..c94d753 100644
--- a/build/main.S
+++ b/build/main.S
@@ -824,7 +824,7 @@ main:
 	.byte	0
 	.uleb128 0xa
 	.4byte	.LASF996
-	.byte	0x29
+	.byte	0x2a
 	.4byte	0x3cd
 	.uleb128 0x6
 	.4byte	0x88
diff --git a/build/main.i b/build/main.i
index f00220b..e5271b3 100644
--- a/build/main.i
+++ b/build/main.i
@@ -2144,10 +2144,11 @@ typedef enum {
 } GPIO_MODE;
 
 void gpio_set_mode(uint16_t pin, GPIO_MODE mode);
+void gpio_set_af(uint16_t pin, uint8_t af);
 void gpio_write(uint16_t pin, 
-# 41 "src/gpio.h" 3 4
+# 42 "src/gpio.h" 3 4
                              _Bool 
-# 41 "src/gpio.h"
+# 42 "src/gpio.h"
                                   val);
 # 6 "src/main.c" 2
 # 1 "src/flash.h" 1
diff --git a/build/main.o b/build/main.o
index e3c3732..87fe3e8 100644
Binary files a/build/main.o and b/build/main.o differ
diff --git a/src/gpio.c b/src/gpio.c
index b92dd26..fa63bb9 100644
--- a/src/gpio.c
+++ b/src/gpio.c
@@ -10,6 +10,18 @@ void gpio_set_mode(uint16_t pin, GPIO_MODE mode) {
   gpio->MODER |= (mode & 0b11) << (pn * 2);   // Set new mode. Each pin uses 2 bits
 }
 
+void gpio_set_af(uint16_t pin, uint8_t af) {
+  struct gpio *gpio = GPIO(PINPORT(pin));
+  int pn = PINNUM(pin);
+  if (pn < 8) {
+	gpio->AFRL &= ~(0b1111 << (pn * 4)); // Each pin uses 4 bits
+	gpio->AFRL |= (af & 0b1111) << (pn * 4);
+  } else {
+	gpio->AFRH &= ~(0b1111 << (pn * 4)); // Each pin uses 4 bits
+	gpio->AFRH |= (af & 0b1111) << (pn * 4);
+  }
+}
+
 void gpio_write(uint16_t pin, bool val) {
   struct gpio *gpio = GPIO(PINPORT(pin));
   gpio->BSRR = (0b0011 << PINNUM(pin)) << (val ? 0 : 16);
diff --git a/src/gpio.h b/src/gpio.h
index bad0e48..298fd88 100644
--- a/src/gpio.h
+++ b/src/gpio.h
@@ -38,6 +38,7 @@ typedef enum {
 } GPIO_MODE;
 
 void gpio_set_mode(uint16_t pin, GPIO_MODE mode);
+void gpio_set_af(uint16_t pin, uint8_t af);
 void gpio_write(uint16_t pin, bool val);
 
 #endif