diff --git a/src/Makefile b/src/Makefile
index b316bb66..92667b2a 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -5,4 +5,4 @@ src-$(CONFIG_HAVE_GPIO) += gpiocmds.c stepper.c endstop.c
 src-$(CONFIG_HAVE_GPIO_ADC) += adccmds.c
 src-$(CONFIG_HAVE_GPIO_SPI) += spicmds.c
 src-$(CONFIG_HAVE_GPIO_HARD_PWM) += pwmcmds.c
-src-$(CONFIG_HAVE_USER_INTERFACE) += lcd_st7920.c
+src-$(CONFIG_HAVE_USER_INTERFACE) += lcd_st7920.c lcd_hd44780.c
diff --git a/src/lcd_hd44780.c b/src/lcd_hd44780.c
new file mode 100644
index 00000000..9c23814b
--- /dev/null
+++ b/src/lcd_hd44780.c
@@ -0,0 +1,132 @@
+// Commands for sending messages to a 4-bit hd44780 lcd driver
+//
+// Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "basecmd.h" // oid_alloc
+#include "board/gpio.h" // gpio_out_write
+#include "board/irq.h" // irq_disable
+#include "board/misc.h" // timer_from_us
+#include "command.h" // DECL_COMMAND
+#include "sched.h" // DECL_SHUTDOWN
+
+struct hd44780 {
+    uint32_t last_cmd_time, cmd_wait_ticks;
+    uint8_t last;
+    struct gpio_out rs, e, d4, d5, d6, d7;
+};
+
+
+/****************************************************************
+ * Transmit functions
+ ****************************************************************/
+
+// Write 4 bits to the hd44780 using the 4bit parallel interface
+static __always_inline void
+hd44780_xmit_bits(uint8_t toggle, struct gpio_out e, struct gpio_out d4
+                  , struct gpio_out d5, struct gpio_out d6, struct gpio_out d7)
+{
+    gpio_out_toggle(e);
+    if (toggle & 0x10)
+        gpio_out_toggle(d4);
+    if (toggle & 0x20)
+        gpio_out_toggle(d5);
+    if (toggle & 0x40)
+        gpio_out_toggle(d6);
+    if (toggle & 0x80)
+        gpio_out_toggle(d7);
+    gpio_out_toggle(e);
+}
+
+// Transmit 8 bits to the chip
+static void
+hd44780_xmit_byte(struct hd44780 *h, uint8_t data)
+{
+    struct gpio_out e = h->e, d4 = h->d4, d5 = h->d5, d6 = h->d6, d7 = h->d7;
+    hd44780_xmit_bits(h->last ^ data, e, d4, d5, d6, d7);
+    h->last = data << 4;
+    hd44780_xmit_bits(data ^ h->last, e, d4, d5, d6, d7);
+}
+
+// Transmit a series of bytes to the chip
+static void
+hd44780_xmit(struct hd44780 *h, uint8_t len, uint8_t *data)
+{
+    uint32_t last_cmd_time=h->last_cmd_time, cmd_wait_ticks=h->cmd_wait_ticks;
+    while (len--) {
+        uint8_t b = *data++;
+        while (timer_read_time() - last_cmd_time < cmd_wait_ticks)
+            irq_poll();
+        hd44780_xmit_byte(h, b);
+        last_cmd_time = timer_read_time();
+    }
+    h->last_cmd_time = last_cmd_time;
+}
+
+
+/****************************************************************
+ * Interface
+ ****************************************************************/
+
+void
+command_config_hd44780(uint32_t *args)
+{
+    struct hd44780 *h = oid_alloc(args[0], command_config_hd44780, sizeof(*h));
+    h->rs = gpio_out_setup(args[1], 0);
+    h->e = gpio_out_setup(args[2], 0);
+    h->d4 = gpio_out_setup(args[3], 0);
+    h->d5 = gpio_out_setup(args[4], 0);
+    h->d6 = gpio_out_setup(args[5], 0);
+    h->d7 = gpio_out_setup(args[6], 0);
+
+    // Calibrate cmd_wait_ticks
+    irq_disable();
+    uint32_t start = timer_read_time();
+    hd44780_xmit_byte(h, 0);
+    uint32_t end = timer_read_time();
+    irq_enable();
+    uint32_t diff = end - start, delay_ticks = args[7];
+    if (delay_ticks > diff)
+        h->cmd_wait_ticks = delay_ticks - diff;
+}
+DECL_COMMAND(command_config_hd44780,
+             "config_hd44780 oid=%c rs_pin=%u e_pin=%u"
+             " d4_pin=%u d5_pin=%u d6_pin=%u d7_pin=%u delay_ticks=%u");
+
+void
+command_hd44780_send_cmds(uint32_t *args)
+{
+    struct hd44780 *h = oid_lookup(args[0], command_config_hd44780);
+    gpio_out_write(h->rs, 0);
+    uint8_t len = args[1], *cmds = (void*)(size_t)args[2];
+    hd44780_xmit(h, len, cmds);
+}
+DECL_COMMAND(command_hd44780_send_cmds, "hd44780_send_cmds oid=%c cmds=%*s");
+
+void
+command_hd44780_send_data(uint32_t *args)
+{
+    struct hd44780 *h = oid_lookup(args[0], command_config_hd44780);
+    gpio_out_write(h->rs, 1);
+    uint8_t len = args[1], *data = (void*)(size_t)args[2];
+    hd44780_xmit(h, len, data);
+}
+DECL_COMMAND(command_hd44780_send_data, "hd44780_send_data oid=%c data=%*s");
+
+void
+hd44780_shutdown(void)
+{
+    uint8_t i;
+    struct hd44780 *h;
+    foreach_oid(i, h, command_config_hd44780) {
+        gpio_out_write(h->rs, 0);
+        gpio_out_write(h->e, 0);
+        gpio_out_write(h->d4, 0);
+        gpio_out_write(h->d5, 0);
+        gpio_out_write(h->d6, 0);
+        gpio_out_write(h->d7, 0);
+        h->last = 0;
+    }
+}
+DECL_SHUTDOWN(hd44780_shutdown);