diff --git a/main.c b/main.c
index f8ecd15..3d68511 100644
--- a/main.c
+++ b/main.c
@@ -56,11 +56,17 @@ static void clock_setup(void)
 {
 	rcc_clock_setup_in_hse_8mhz_out_72mhz(); // use 8 MHz high speed external clock to generate 72 MHz internal clock
 	rcc_periph_clock_enable(LED_RCC); //enable clock for LED
+	rcc_periph_clock_enable(VFD_RCC); //enable clock for VFD
 }
 
 static void gpio_setup(void)
 {
-	gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, LED_PIN); // set LED pin to 'output push-pull'	
+	gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, LED_PIN); // set LED pin to 'output push-pull'
+	gpio_set_mode(VFD_PORT, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, VFD_STR); // set VFD pin to 'output push-pull'
+	gpio_set_mode(VFD_PORT, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, VFD_NLE); // set VFD pin to 'output push-pull'
+	gpio_set_mode(VFD_PORT, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, VFD_CLK); // set VFD pin to 'output push-pull'
+	gpio_set_mode(VFD_PORT, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, VFD_DIN); // set VFD pin to 'output push-pull'
+	
 }
 
 int main(void)
@@ -70,22 +76,59 @@ int main(void)
 	clock_setup(); // setup main clock
 	gpio_setup(); // setup main inputs/ouputs
 	usart_setup(); // setup USART (for printing)
-	cdcacm_setup(); // setup USB CDC ACM (for printing)
+	cdcacm_setup(); // setup USART (for printing)
 	
 	setbuf(stdout, NULL); // set standard out buffer to NULL to immediately print	
 	setbuf(stderr, NULL); // set standard error buffer to NULL to immediately print
 
-	printf("welcome to the STM32F1 CuVoodoo example code\n");
+	printf("welcome to the STM32F1 CuVoodoo display driver\n");
+	
+	printf("sending VFD data\n");
+	gpio_set(VFD_PORT, VFD_STR); // disable HV output
+	gpio_clear(VFD_PORT, VFD_NLE); // do not latch data
+	gpio_set(VFD_PORT, VFD_CLK); // clock is idle high
 
+	bool vfd_transmit = false;
+	uint32_t vfd_data[3] = {~0,~0,~0};
+	uint8_t bit_flip = 0;
 	/* blink the LED with every transmitted character */
 	while (1) {
 		while (usart_received) { // echo every received character
 			gpio_toggle(LED_PORT, LED_PIN); // toggle LED
 			printf("%c",usart_getchar()); // transmit receive character
+			vfd_transmit = true;
 		}
 		while (cdcacm_received) { // echo every received character
 			gpio_toggle(LED_PORT, LED_PIN); // toggle LED
 			printf("%c",cdcacm_getchar()); // transmit receive character
+			vfd_transmit = true;
+		}
+		while (vfd_transmit) {
+			vfd_transmit = false;
+			/* send data to VFD (data valid on clock high) to 3x32 lines */
+			gpio_set(VFD_PORT, VFD_STR); // disable HV output
+			gpio_clear(VFD_PORT, VFD_NLE); // do not latch data
+			gpio_set(VFD_PORT, VFD_CLK); // clock is idle high	
+			for (uint8_t i=0; i<3; i++) {
+				printf("%08lx ", vfd_data[i]);
+				for (uint8_t b=0; b<32; b++) {
+					gpio_clear(VFD_PORT, VFD_CLK);
+					if (vfd_data[i]&(1<<b)) {
+						gpio_set(VFD_PORT, VFD_DIN);
+					} else {
+						gpio_clear(VFD_PORT, VFD_DIN);
+					}
+					gpio_set(VFD_PORT, VFD_CLK);
+				}
+				vfd_data[i] = ~0;
+			}
+			gpio_set(VFD_PORT, VFD_NLE); // latch data
+			gpio_clear(VFD_PORT, VFD_STR); // enable HV output
+			printf("\n");
+			
+			/* flip bit */
+			vfd_data[bit_flip/32] = ~(1<<(bit_flip%32));
+			bit_flip = (bit_flip+1)%(3*32);
 		}
 		__WFI(); // go to sleep
 	}
diff --git a/main.h b/main.h
index 6d2e1eb..01a5e8e 100644
--- a/main.h
+++ b/main.h
@@ -19,5 +19,13 @@
 #define LED_PORT GPIOA
 #define LED_PIN	GPIO1
 
+/* supertex HV518 vacuum fluorescent display pins */
+#define VFD_RCC RCC_GPIOA
+#define VFD_PORT GPIOA
+#define VFD_STR GPIO4
+#define VFD_NLE GPIO5
+#define VFD_CLK GPIO6
+#define VFD_DIN GPIO7
+
 /* default output (i.e. for printf) */
 int _write(int file, char *ptr, int len);