spark_abacus/lib/vfd_hv518.c

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/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
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/** library to drive vacuum fluorescent display using supertex HV518 shift register VFD drivers (code)
* @details the current configuration is for a VFD extracted from a Samsung SER-6500 cash register
* @file vfd_hv518.c
* @author King Kévin <kingkevin@cuvoodoo.info>
* @date 2016
* @note peripherals used: SPI @ref vfd_hv518_spi , GPIO @ref vfd_hv518_gpio , timer @ref vfd_hv518_timer
*/
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // general utilities
/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/rcc.h> // real-time control clock library
#include <libopencm3/stm32/gpio.h> // general purpose input output library
#include <libopencm3/stm32/spi.h> // SPI library
#include <libopencm3/stm32/timer.h> // timer library
#include <libopencm3/cm3/nvic.h> // interrupt handler
#include "global.h" // global definitions
#include "vfd_hv518.h" // VFD library API
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/** @defgroup vfd_hv518_gpio GPIO to control supertex HV518 VFD drivers
* @{
*/
#define VFD_PORT GPIOA /**< GPIO port */
#define VFD_PORT_RCC RCC_GPIOA /**< GPIO port peripheral clock */
#define VFD_STR GPIO6 /**< strobe pin to enable high voltage output, high voltage is output on low */
#define VFD_NLE GPIO4 /**< latch enable pin, stores the shifted data on low, output the parallel data on high */
/** @} */
/** @defgroup vfd_hv518_spi SPI to send data to supertex HV518 VFD drivers
* @{
*/
#define VFD_SPI_RCC RCC_SPI1 /**< SPI peripheral */
#define VFD_SPI_PORT GPIOA /**< GPIO port */
#define VFD_SPI_PORT_RCC RCC_GPIOA /**< GPIO port peripheral clock */
#define VFD_SPI_IRQ NVIC_SPI1_IRQ /**< SPI peripheral interrupt signal */
#define VFD_SPI_ISR spi1_isr /**< SPI interrupt service routine */
#define VFD_CLK GPIO_SPI1_SCK /**< clock signal */
#define VFD_DIN GPIO_SPI1_MOSI /**< data input, where the data is shifted to */
/** @} */
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/** @defgroup vfd_hv518_timer timer for automatic display blocks refresh
* @{
*/
#define VFD_TIMER_RCC RCC_TIM2 /**< timer peripheral clock */
#define VFD_TIMER_IRQ NVIC_TIM2_IRQ /**< timer interrupt signal */
#define VFD_TIMER_ISR tim2_isr /**< timer interrupt service routine */
/** @} */
/** ASCII characters encoded for the 7 segments digit block
* @note starts with space
*/
static const uint8_t ascii_7segments[] = {
0b00000000, // space
0b00110000, // ! (I)
0b00100010, // "
0b01011100, // # (o)
0b01101101, // $ (s)
0b01010010, // % (/)
0b01111101, // & (6)
0b00100000, // '
0b00111001, // ( ([)
0b00001111, // )
0b01110000, // *
0b01000110, // +
0b00010000, // ,
0b01000000, // -
0b00010000, // . (,)
0b01010010, // /
0b00111111, // 0
0b00000110, // 1
0b01011011, // 2
0b01001111, // 3
0b01100110, // 4
0b01101101, // 5
0b01111101, // 6
0b00000111, // 7
0b01111111, // 8
0b01101111, // 9
0b01001000, // : (=)
0b01001000, // ; (=)
0b01011000, // <
0b01001000, // =
0b01001100, // >
0b01010011, // ?
0b01111011, // @
0b01110111, // A
0b01111111, // B
0b00111001, // C
0b01011110, // D
0b01111001, // E
0b01110001, // F
0b00111101, // G
0b01110110, // H
0b00110000, // I
0b00011110, // J
0b01110110, // K
0b00111000, // L
0b00110111, // M
0b00110111, // N
0b00111111, // O
0b01110011, // P
0b01101011, // Q
0b00110011, // R
0b01101101, // S
0b01111000, // T
0b00111110, // U
0b00111110, // V (U)
0b00111110, // W (U)
0b01110110, // X (H)
0b01101110, // Y
0b01011011, // Z
0b00111001, // [
0b01100100, // '\'
0b00001111, // /
0b00100011, // ^
0b00001000, // _
0b00000010, // `
0b01011111, // a
0b01111100, // b
0b01011000, // c
0b01011110, // d
0b01111011, // e
0b01110001, // f
0b01101111, // g
0b01110100, // h
0b00010000, // i
0b00001100, // j
0b01110110, // k
0b00110000, // l
0b01010100, // m
0b01010100, // n
0b01011100, // o
0b01110011, // p
0b01100111, // q
0b01010000, // r
0b01101101, // s
0b01111000, // t
0b00011100, // u
0b00011100, // v (u)
0b00011100, // w (u)
0b01110110, // x
0b01101110, // y
0b01011011, // z
0b00111001, // { ([)
0b00110000, // |
0b00001111, // } ([)
0b01000000, // ~
};
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/** font for the 5x7 dot matrix block
* @details first value is left-most line, LSB is top dot, MSB is not used
* @note from http://sunge.awardspace.com/glcd-sd/node4.html
*/
static const uint8_t font5x7[][5] = {
{0x00, 0x00, 0x00, 0x00, 0x00}, // (space)
{0x00, 0x00, 0x5F, 0x00, 0x00}, // !
{0x00, 0x07, 0x00, 0x07, 0x00}, // "
{0x14, 0x7F, 0x14, 0x7F, 0x14}, // #
{0x24, 0x2A, 0x7F, 0x2A, 0x12}, // $
{0x23, 0x13, 0x08, 0x64, 0x62}, // %
{0x36, 0x49, 0x55, 0x22, 0x50}, // &
{0x00, 0x05, 0x03, 0x00, 0x00}, // '
{0x00, 0x1C, 0x22, 0x41, 0x00}, // (
{0x00, 0x41, 0x22, 0x1C, 0x00}, // )
{0x08, 0x2A, 0x1C, 0x2A, 0x08}, // *
{0x08, 0x08, 0x3E, 0x08, 0x08}, // +
{0x00, 0x50, 0x30, 0x00, 0x00}, // ,
{0x08, 0x08, 0x08, 0x08, 0x08}, // -
{0x00, 0x60, 0x60, 0x00, 0x00}, // .
{0x20, 0x10, 0x08, 0x04, 0x02}, // /
{0x3E, 0x51, 0x49, 0x45, 0x3E}, // 0
{0x00, 0x42, 0x7F, 0x40, 0x00}, // 1
{0x42, 0x61, 0x51, 0x49, 0x46}, // 2
{0x21, 0x41, 0x45, 0x4B, 0x31}, // 3
{0x18, 0x14, 0x12, 0x7F, 0x10}, // 4
{0x27, 0x45, 0x45, 0x45, 0x39}, // 5
{0x3C, 0x4A, 0x49, 0x49, 0x30}, // 6
{0x01, 0x71, 0x09, 0x05, 0x03}, // 7
{0x36, 0x49, 0x49, 0x49, 0x36}, // 8
{0x06, 0x49, 0x49, 0x29, 0x1E}, // 9
{0x00, 0x36, 0x36, 0x00, 0x00}, // :
{0x00, 0x56, 0x36, 0x00, 0x00}, // ;
{0x00, 0x08, 0x14, 0x22, 0x41}, // <
{0x14, 0x14, 0x14, 0x14, 0x14}, // =
{0x41, 0x22, 0x14, 0x08, 0x00}, // >
{0x02, 0x01, 0x51, 0x09, 0x06}, // ?
{0x32, 0x49, 0x79, 0x41, 0x3E}, // @
{0x7E, 0x11, 0x11, 0x11, 0x7E}, // A
{0x7F, 0x49, 0x49, 0x49, 0x36}, // B
{0x3E, 0x41, 0x41, 0x41, 0x22}, // C
{0x7F, 0x41, 0x41, 0x22, 0x1C}, // D
{0x7F, 0x49, 0x49, 0x49, 0x41}, // E
{0x7F, 0x09, 0x09, 0x01, 0x01}, // F
{0x3E, 0x41, 0x41, 0x51, 0x32}, // G
{0x7F, 0x08, 0x08, 0x08, 0x7F}, // H
{0x00, 0x41, 0x7F, 0x41, 0x00}, // I
{0x20, 0x40, 0x41, 0x3F, 0x01}, // J
{0x7F, 0x08, 0x14, 0x22, 0x41}, // K
{0x7F, 0x40, 0x40, 0x40, 0x40}, // L
{0x7F, 0x02, 0x04, 0x02, 0x7F}, // M
{0x7F, 0x04, 0x08, 0x10, 0x7F}, // N
{0x3E, 0x41, 0x41, 0x41, 0x3E}, // O
{0x7F, 0x09, 0x09, 0x09, 0x06}, // P
{0x3E, 0x41, 0x51, 0x21, 0x5E}, // Q
{0x7F, 0x09, 0x19, 0x29, 0x46}, // R
{0x46, 0x49, 0x49, 0x49, 0x31}, // S
{0x01, 0x01, 0x7F, 0x01, 0x01}, // T
{0x3F, 0x40, 0x40, 0x40, 0x3F}, // U
{0x1F, 0x20, 0x40, 0x20, 0x1F}, // V
{0x7F, 0x20, 0x18, 0x20, 0x7F}, // W
{0x63, 0x14, 0x08, 0x14, 0x63}, // X
{0x03, 0x04, 0x78, 0x04, 0x03}, // Y
{0x61, 0x51, 0x49, 0x45, 0x43}, // Z
{0x00, 0x00, 0x7F, 0x41, 0x41}, // [
{0x02, 0x04, 0x08, 0x10, 0x20}, // '\'
{0x41, 0x41, 0x7F, 0x00, 0x00}, // ]
{0x04, 0x02, 0x01, 0x02, 0x04}, // ^
{0x40, 0x40, 0x40, 0x40, 0x40}, // _
{0x00, 0x01, 0x02, 0x04, 0x00}, // `
{0x20, 0x54, 0x54, 0x54, 0x78}, // a
{0x7F, 0x48, 0x44, 0x44, 0x38}, // b
{0x38, 0x44, 0x44, 0x44, 0x20}, // c
{0x38, 0x44, 0x44, 0x48, 0x7F}, // d
{0x38, 0x54, 0x54, 0x54, 0x18}, // e
{0x08, 0x7E, 0x09, 0x01, 0x02}, // f
{0x08, 0x14, 0x54, 0x54, 0x3C}, // g
{0x7F, 0x08, 0x04, 0x04, 0x78}, // h
{0x00, 0x44, 0x7D, 0x40, 0x00}, // i
{0x20, 0x40, 0x44, 0x3D, 0x00}, // j
{0x00, 0x7F, 0x10, 0x28, 0x44}, // k
{0x00, 0x41, 0x7F, 0x40, 0x00}, // l
{0x7C, 0x04, 0x18, 0x04, 0x78}, // m
{0x7C, 0x08, 0x04, 0x04, 0x78}, // n
{0x38, 0x44, 0x44, 0x44, 0x38}, // o
{0x7C, 0x14, 0x14, 0x14, 0x08}, // p
{0x08, 0x14, 0x14, 0x18, 0x7C}, // q
{0x7C, 0x08, 0x04, 0x04, 0x08}, // r
{0x48, 0x54, 0x54, 0x54, 0x20}, // s
{0x04, 0x3F, 0x44, 0x40, 0x20}, // t
{0x3C, 0x40, 0x40, 0x20, 0x7C}, // u
{0x1C, 0x20, 0x40, 0x20, 0x1C}, // v
{0x3C, 0x40, 0x30, 0x40, 0x3C}, // w
{0x44, 0x28, 0x10, 0x28, 0x44}, // x
{0x0C, 0x50, 0x50, 0x50, 0x3C}, // y
{0x44, 0x64, 0x54, 0x4C, 0x44}, // z
{0x00, 0x08, 0x36, 0x41, 0x00}, // {
{0x00, 0x00, 0x7F, 0x00, 0x00}, // |
{0x00, 0x41, 0x36, 0x08, 0x00}, // }
{0b00001000, 0b00000100, 0b00001100, 0b00001000, 0b00000100} // ~
};
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/** pictures for the 5x7 dot matrix block
* @details first value is left-most line, LSB is top dot, MSB is not used
*/
static const uint8_t pict5x7[][5] = {
{0x08, 0x08, 0x2A, 0x1C, 0x08}, // ->
{0x08, 0x1C, 0x2A, 0x08, 0x08}, // <-
{0b01110000, 0b01110000, 0b01111010, 0b01111100, 0b01011000}, // bunny side 1
{0b00100000, 0b01110000, 0b01110010, 0b01111100, 0b01011000}, // bunny side 2
{0b00111110, 0b01001001, 0b01010110, 0b01001001, 0b00111110}, // bunny face 1
{0b00111110, 0b01010001, 0b01100110, 0b01010001, 0b00111110}, // bunny face 2
{0b00111000, 0b01010111, 0b01100100, 0b01010111, 0b00111000}, // bunny face 3
{0b00111000, 0b01001111, 0b01010100, 0b01001111, 0b00111000}, // bunny face 4
{0b00111000, 0b01011110, 0b01101000, 0b01011110, 0b00111000}, // bunny face 5
{0b01000001, 0b00110110, 0b00001000, 0b00110110, 0b01000001}, // cross 1
{~0b01000001, ~0b00110110, ~0b00001000, ~0b00110110, ~0b01000001}, // cross 1 negated
{0b00100010, 0b00010100, 0b00001000, 0b00010100, 0b00100010}, // cross 2
{~0b00100010, ~0b00010100, ~0b00001000, ~0b00010100, ~0b00100010}, // cross 2 negated
{0x00, 0x00, 0x00, 0x00, 0x00} // nothing
};
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/** the 32 bits values to be shifted out to the VFD driver
* @note split into 16 bit for SPI transfer
* @note since the bits for digits and matrix are independent, they can be combined
* @note we have more matrix (12) than digits (10)
*/
static uint16_t driver_data[VFD_MATRIX][VFD_DRIVERS*2] = {0};
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/** which driver data is being transmitted */
static volatile uint8_t spi_i = 0;
/** which grid/part to activate
* @note digits and matrix can be combined
*/
static volatile uint8_t vfd_grid = 0;
/** the bits used for selecting then digit and 7 segment anodes
* @note for the second driver
*/
static const uint32_t digit_mask = 0x00fffff0;
void vfd_digit(uint8_t nb, char c)
{
if (!(nb<VFD_DIGITS)) { // check the digit exists
return;
}
uint32_t digit_data = 0; // the data to be shifted out for the driver (for the second driver)
digit_data = 1<<(4+(9-nb)); // select digit
/* encode segment
* here the bit order (classic 7 segment + underline and dot)
* 3_
* 8|9_|4
* 7|6_|5.1
* 0_2,
* */
if (false) { // add the underline (not encoded)
digit_data |= (1<<(14));
}
if (c&0x80) { // add the dot (encoded in the 8th bit)
digit_data |= (1<<(15));
}
if (false) { // add the comma (not encoded)
digit_data |= (1<<(16));
}
c &= 0x7f; // only take the ASCII part
if (c>=' ') { // only take printable characters
uint8_t i = c-' '; // get index for character
if (i<LENGTH(ascii_7segments)) {
digit_data |= (ascii_7segments[i]<<(17)); // add encoded segments to memory
}
}
digit_data &= digit_mask; // be sure only the bits for the digit are used
digit_data |= (driver_data[nb][2]+(driver_data[nb][3]<<16))&~digit_mask; // get the existing data and add the bits for the digit
driver_data[nb][2] = digit_data; // write back data (least significant half)
driver_data[nb][3] = (digit_data>>16); // write back data (most significant half)
}
void vfd_matrix(uint8_t nb, char c)
{
// check the matrix exists
if (!(nb<VFD_MATRIX)) {
return;
}
uint32_t matrix_data[VFD_DRIVERS] = {0}; // the data to be shifted out for the driver
// select matrix
if (nb<4) {
matrix_data[1] = 1<<(3-nb);
} else {
matrix_data[0] = 1<<(35-nb);
}
if ((c<0x80) && (c>=' ')) { // only take printable characters
uint8_t i = c-' '; // get index for character
if (i<LENGTH(font5x7)) {
matrix_data[1] |= font5x7[i][0]<<24;
matrix_data[2] |= font5x7[i][1]<<0;
matrix_data[2] |= font5x7[i][2]<<8;
matrix_data[2] |= font5x7[i][3]<<16;
matrix_data[2] |= font5x7[i][4]<<24;
}
} else if (c>0x7f) { // the non ASCII character are used for pictures
uint8_t i = c-0x80; // get index for character
if (i<LENGTH(pict5x7)) {
matrix_data[1] |= pict5x7[i][0]<<24;
matrix_data[2] |= pict5x7[i][1]<<0;
matrix_data[2] |= pict5x7[i][2]<<8;
matrix_data[2] |= pict5x7[i][3]<<16;
matrix_data[2] |= pict5x7[i][4]<<24;
}
}
matrix_data[1] &= ~digit_mask; // be sure only the bits for the matrix are used
matrix_data[1] |= (driver_data[nb][2]+(driver_data[nb][3]<<16))&digit_mask; // get the existing data for the digit
// prepare the data for SPI to shift it out
for (uint8_t i=0; i<LENGTH(matrix_data); i++) {
driver_data[nb][i*2] = matrix_data[i];
driver_data[nb][i*2+1] = matrix_data[i]>>16;
}
}
void vfd_clear(void)
{
for (uint8_t i=0; i<LENGTH(driver_data); i++) {
for (uint8_t j=0; j<LENGTH(driver_data[0]); j++) {
driver_data[i][j] = 0;
}
}
}
void vfd_test(void)
{
for (uint8_t i=0; i<LENGTH(driver_data); i++) {
for (uint8_t j=0; j<LENGTH(driver_data[0]); j++) {
driver_data[i][j] = ~0;
}
}
}
void vfd_on(void)
{
gpio_clear(VFD_PORT, VFD_STR); // enable HV output
timer_enable_counter(VFD_TIMER); // start timer to periodically output that to the parts
}
void vfd_off(void)
{
gpio_set(VFD_PORT, VFD_STR); // disable HV output
timer_disable_counter(VFD_TIMER); // stop timer to periodically output that to the parts
}
void vfd_setup(void)
{
/* setup GPIO to control the VFD */
rcc_periph_clock_enable(VFD_PORT_RCC); // enable clock for VFD GPIO
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(VFD_PORT, VFD_STR); // disable HV output
gpio_clear(VFD_PORT, VFD_NLE); // do not output latched data
/* setup SPI to transmit data */
rcc_periph_clock_enable(VFD_SPI_RCC); // enable SPI clock
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rcc_periph_clock_enable(VFD_SPI_PORT_RCC); // enable clock for VFD SPI GPIO
gpio_set_mode(VFD_SPI_PORT, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, VFD_CLK); // set VFD pin to alternative function push-pull
gpio_set_mode(VFD_SPI_PORT, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, VFD_DIN); // set VFD pin to alternative function push-pull
spi_reset(VFD_SPI); // clear SPI values
/* set SPI:
* - use VFD_SPI port
* - divide clock by 8 for generating the baudrate (F_PCLK1 is 36MHz, max HV518 is 6MHz)
* - clock idle high polarity
* - data is valid on rising edge (second clock phase)
* - send 16 bits at a time
* - send least significant bit first (that's how I coded the data)
*/
spi_init_master(VFD_SPI, SPI_CR1_BAUDRATE_FPCLK_DIV_8, SPI_CR1_CPOL_CLK_TO_1_WHEN_IDLE, SPI_CR1_CPHA_CLK_TRANSITION_2, SPI_CR1_DFF_16BIT, SPI_CR1_LSBFIRST);
//spi_set_bidirectional_transmit_only_mode(VFD_SPI); // only use MOSI to transmit
spi_set_unidirectional_mode(VFD_SPI); // MISO is unused
/* set NSS high to enable transmission
* the NSS in STM32 can not be used as hardware slave select
* RM0008 reference manual 25.3.1 is misleading
* when hardware NSS is used and output is enabled NSS never goes up after transmission, even if SPI is disabled
* when software NSS is used, NSS can not be set high again, even when writing to the register
* the slave select must be done manually using GPIO */
spi_enable_software_slave_management(VFD_SPI);
spi_set_nss_high(VFD_SPI); // set NSS high
nvic_enable_irq(VFD_SPI_IRQ); // enable SPI interrupt
spi_enable(VFD_SPI); // enable SPI (the tx empty interrupt will trigger)
/* setup timer to refresh display */
rcc_periph_clock_enable(VFD_TIMER_RCC); // enable clock for timer block
timer_reset(VFD_TIMER); // reset timer state
timer_set_mode(VFD_TIMER, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock,edge alignment (simple count), and count up
timer_set_prescaler(VFD_TIMER, (SYSTEM_CLOCK_FREQ/(1<<16))-1); // set the prescaler so this 16 bits timer overflows at 1Hz
timer_set_period(VFD_TIMER, 0xffff/LENGTH(driver_data)/100); // set the refresh frequency
timer_enable_irq(VFD_TIMER, TIM_DIER_UIE); // enable interrupt for timer
nvic_enable_irq(VFD_TIMER_IRQ); // allow interrupt for timer
vfd_clear(); // initialize values
}
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/** SPI interrupt service routine called when data has been transmitted */
void VFD_SPI_ISR(void)
{
if (SPI_SR(VFD_SPI) & SPI_SR_TXE) { // transmission buffer empty
if (spi_i<LENGTH(driver_data[0])) { // check if data is available
gpio_clear(VFD_PORT, VFD_NLE); // slave select to latch data
spi_send(VFD_SPI, driver_data[vfd_grid][spi_i++]); // send next data
} else { // all data transmitted
spi_disable_tx_buffer_empty_interrupt(VFD_SPI); // no need to wait for new data
while (SPI_SR(VFD_SPI) & SPI_SR_BSY); // wait for data to be shifted out
spi_disable_tx_buffer_empty_interrupt(VFD_SPI); // no need to wait for new data
gpio_set(VFD_PORT, VFD_NLE); // output latched data
}
}
}
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/** timer interrupt service routine called time passed */
void VFD_TIMER_ISR(void)
{
if (timer_get_flag(VFD_TIMER, TIM_SR_UIF)) { // overflow even happened
timer_clear_flag(VFD_TIMER, TIM_SR_UIF); // clear flag
spi_i = 0; // set the register to shift out
spi_enable_tx_buffer_empty_interrupt(VFD_SPI); // enable TX empty interrupt
vfd_grid = (vfd_grid+1)%LENGTH(driver_data); // got to next segment
}
}