diff --git a/src/keyboard/controller.c b/src/keyboard/controller.c
index 3c184cc..b97b112 100644
--- a/src/keyboard/controller.c
+++ b/src/keyboard/controller.c
@@ -438,3 +438,61 @@ uint8_t teensy_update_matrix(bool matrix[KB_ROWS][KB_COLUMNS]) {
 
 	return 0;  // success
 }
+
+// ----------------------------------------------------------------------------
+
+void twi_init(void) {
+	// set the prescaler value to 0
+	TWSR &= ~( (1<<TWPS1)|(1<<TWPS0) );
+	// set the bit rate
+	// - TWBR should be 10 or higher (datasheet section 20.5.2)
+	// - TWI_FREQ should be 400000 (400kHz) max (datasheet section 20.1)
+	TWBR = ((F_CPU / TWI_FREQ) - 16) / 2;
+}
+
+uint8_t twi_start(void) {
+	// send start
+	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTA);
+	// wait for transmission to complete
+	while (!(TWCR & (1<<TWINT)));
+	// if it didn't work, return the status code (else return 0)
+	if ( (TW_STATUS != TW_START) &&
+	     (TW_STATUS != TW_REP_START) )
+		return TW_STATUS;  // error
+	return 0;  // success
+}
+
+void twi_stop(void) {
+	// send stop
+	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
+	// wait for transmission to complete
+	while (TWCR & (1<<TWSTO));
+}
+
+uint8_t twi_send(uint8_t data) {
+	// load data into the data register
+	TWDR = data;
+	// send data
+	TWCR = (1<<TWINT)|(1<<TWEN);
+	// wait for transmission to complete
+	while (!(TWCR & (1<<TWINT)));
+	// if it didn't work, return the status code (else return 0)
+	if ( (TW_STATUS != TW_MT_SLA_ACK)  &&
+	     (TW_STATUS != TW_MT_DATA_ACK) &&
+	     (TW_STATUS != TW_MR_SLA_ACK) )
+		return TW_STATUS;  // error
+	return 0;  // success
+}
+
+uint8_t twi_read(uint8_t * data) {
+	// read 1 byte to TWDR, send ACK
+	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA);
+	// wait for transmission to complete
+	while (!(TWCR & (1<<TWINT)));
+	// set data variable
+	*data = TWDR;
+	// if it didn't work, return the status code (else return 0)
+	if (TW_STATUS != TW_MR_DATA_ACK)
+		return TW_STATUS;  // error
+	return 0;  // success
+}
diff --git a/src/keyboard/controller.h b/src/keyboard/controller.h
index 82aea58..13b7371 100644
--- a/src/keyboard/controller.h
+++ b/src/keyboard/controller.h
@@ -8,13 +8,9 @@
 
 #pragma once
 
-// for "lib/twi.h"
-#define TWI_FREQ 400000
-
 #include <stdbool.h>
 #include <stdint.h>
 #include <util/twi.h>
-#include "../lib/teensy-2-0.h"
 #include "./options.h"
 #include "./matrix.h"
 #include <avr/io.h>
@@ -78,3 +74,13 @@ uint8_t teensy_update_matrix( bool matrix[KB_ROWS][KB_COLUMNS] );
 		_kb_led_2_set_percent(n);                   \
 		_kb_led_3_set_percent(n);                   \
   } while(0)
+
+// --------------------------------------------------------------------
+
+#define TWI_FREQ 400000
+
+void    twi_init  (void);
+uint8_t twi_start (void);
+void    twi_stop  (void);
+uint8_t twi_send  (uint8_t data);
+uint8_t twi_read  (uint8_t * data);
diff --git a/src/lib/teensy-2-0.c b/src/lib/teensy-2-0.c
deleted file mode 100644
index 45cf275..0000000
--- a/src/lib/teensy-2-0.c
+++ /dev/null
@@ -1,81 +0,0 @@
-/* ----------------------------------------------------------------------------
- * Very simple Teensy 2.0 TWI library : code
- *
- * - This is mostly straight from the datasheet, section 20.6.6, figure 20-11
- *   (the code example in C), and section 20.8.1, figure 20-12
- * - Also see the documentation for `<util/teensy-2-0.h>` at
- *   <http://www.nongnu.org/avr-libc/user-manual/group__util__teensy-2-0.html#ga8d3aca0acc182f459a51797321728168>
- *
- * Some other (more complete) TWI libraries for the Teensy 2.0 (and other Atmel
- * processors):
- * - [i2cmaster] (http://homepage.hispeed.ch/peterfleury/i2cmaster.zip)
- *   - written by [peter-fleury] (http://homepage.hispeed.ch/peterfleury/)
- * - [the arduino twi library]
- *   (https://github.com/arduino/Arduino/tree/master/libraries/Wire/utility)
- *   - look for an older version if you need one that doesn't depend on all the
- *     other Arduino stuff
- * ----------------------------------------------------------------------------
- * Copyright (c) 2012 Ben Blazak <benblazak.dev@gmail.com>
- * Released under The MIT License (MIT) (see "license.md")
- * Project located at <https://github.com/benblazak/ergodox-firmware>
- * ------------------------------------------------------------------------- */
-
-#include "./teensy-2-0.h"
-
-// ----------------------------------------------------------------------------
-
-void twi_init(void) {
-	// set the prescaler value to 0
-	TWSR &= ~( (1<<TWPS1)|(1<<TWPS0) );
-	// set the bit rate
-	// - TWBR should be 10 or higher (datasheet section 20.5.2)
-	// - TWI_FREQ should be 400000 (400kHz) max (datasheet section 20.1)
-	TWBR = ((F_CPU / TWI_FREQ) - 16) / 2;
-}
-
-uint8_t twi_start(void) {
-	// send start
-	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTA);
-	// wait for transmission to complete
-	while (!(TWCR & (1<<TWINT)));
-	// if it didn't work, return the status code (else return 0)
-	if ( (TW_STATUS != TW_START) &&
-	     (TW_STATUS != TW_REP_START) )
-		return TW_STATUS;  // error
-	return 0;  // success
-}
-
-void twi_stop(void) {
-	// send stop
-	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
-	// wait for transmission to complete
-	while (TWCR & (1<<TWSTO));
-}
-
-uint8_t twi_send(uint8_t data) {
-	// load data into the data register
-	TWDR = data;
-	// send data
-	TWCR = (1<<TWINT)|(1<<TWEN);
-	// wait for transmission to complete
-	while (!(TWCR & (1<<TWINT)));
-	// if it didn't work, return the status code (else return 0)
-	if ( (TW_STATUS != TW_MT_SLA_ACK)  &&
-	     (TW_STATUS != TW_MT_DATA_ACK) &&
-	     (TW_STATUS != TW_MR_SLA_ACK) )
-		return TW_STATUS;  // error
-	return 0;  // success
-}
-
-uint8_t twi_read(uint8_t * data) {
-	// read 1 byte to TWDR, send ACK
-	TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWEA);
-	// wait for transmission to complete
-	while (!(TWCR & (1<<TWINT)));
-	// set data variable
-	*data = TWDR;
-	// if it didn't work, return the status code (else return 0)
-	if (TW_STATUS != TW_MR_DATA_ACK)
-		return TW_STATUS;  // error
-	return 0;  // success
-}
diff --git a/src/lib/teensy-2-0.h b/src/lib/teensy-2-0.h
deleted file mode 100644
index 8b06961..0000000
--- a/src/lib/teensy-2-0.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* ----------------------------------------------------------------------------
- * Very simple Teensy 2.0 TWI library : exports
- * ----------------------------------------------------------------------------
- * Copyright (c) 2012 Ben Blazak <benblazak.dev@gmail.com>
- * Released under The MIT License (MIT) (see "license.md")
- * Project located at <https://github.com/benblazak/ergodox-firmware>
- * ------------------------------------------------------------------------- */
-
-#pragma once
-#include <util/twi.h>
-
-// --------------------------------------------------------------------
-
-#ifndef TWI_FREQ
-#define TWI_FREQ 100000  // in Hz
-#endif
-
-// --------------------------------------------------------------------
-
-void    twi_init  (void);
-uint8_t twi_start (void);
-void    twi_stop  (void);
-uint8_t twi_send  (uint8_t data);
-uint8_t twi_read  (uint8_t * data);
diff --git a/src/lib/readme.md b/src/lib/teensy-readme.md
similarity index 100%
rename from src/lib/readme.md
rename to src/lib/teensy-readme.md