498 lines
17 KiB
C
498 lines
17 KiB
C
/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** library to drive vacuum fluorescent display using supertex HV518 shift register VFD drivers (code)
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* @details the current configuration is for a VFD extracted from a Samsung SER-6500 cash register
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* @file vfd_hv518.c
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2016
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* @note peripherals used: SPI @ref vfd_hv518_spi , GPIO @ref vfd_hv518_gpio , timer @ref vfd_hv518_timer
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*/
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/* standard libraries */
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#include <stdint.h> // standard integer types
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#include <stdlib.h> // general utilities
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/* STM32 (including CM3) libraries */
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#include <libopencm3/stm32/rcc.h> // real-time control clock library
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#include <libopencm3/stm32/gpio.h> // general purpose input output library
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#include <libopencm3/stm32/spi.h> // SPI library
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#include <libopencm3/stm32/timer.h> // timer library
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#include <libopencm3/cm3/nvic.h> // interrupt handler
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#include "global.h" // global definitions
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#include "vfd_hv518.h" // VFD library API
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/** @defgroup vfd_hv518_gpio GPIO to control supertex HV518 VFD drivers
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* @{
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*/
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#define VFD_PORT GPIOA /**< GPIO port */
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#define VFD_PORT_RCC RCC_GPIOA /**< GPIO port peripheral clock */
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#define VFD_STR GPIO6 /**< strobe pin to enable high voltage output, high voltage is output on low */
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#define VFD_NLE GPIO4 /**< latch enable pin, stores the shifted data on low, output the parallel data on high */
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/** @} */
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/** @defgroup vfd_hv518_spi SPI to send data to supertex HV518 VFD drivers
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* @{
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*/
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#define VFD_SPI_RCC RCC_SPI1 /**< SPI peripheral */
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#define VFD_SPI_PORT GPIOA /**< GPIO port */
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#define VFD_SPI_PORT_RCC RCC_GPIOA /**< GPIO port peripheral clock */
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#define VFD_SPI_IRQ NVIC_SPI1_IRQ /**< SPI peripheral interrupt signal */
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#define VFD_SPI_ISR spi1_isr /**< SPI interrupt service routine */
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#define VFD_CLK GPIO_SPI1_SCK /**< clock signal */
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#define VFD_DIN GPIO_SPI1_MOSI /**< data input, where the data is shifted to */
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/** @} */
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/** @defgroup vfd_hv518_timer timer for automatic display blocks refresh
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* @{
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*/
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#define VFD_TIMER_RCC RCC_TIM2 /**< timer peripheral clock */
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#define VFD_TIMER_IRQ NVIC_TIM2_IRQ /**< timer interrupt signal */
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#define VFD_TIMER_ISR tim2_isr /**< timer interrupt service routine */
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/** @} */
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/** ASCII characters encoded for the 7 segments digit block
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* @note starts with space
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*/
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static const uint8_t ascii_7segments[] = {
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0b00000000, // space
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0b00110000, // ! (I)
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0b00100010, // "
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0b01011100, // # (o)
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0b01101101, // $ (s)
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0b01010010, // % (/)
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0b01111101, // & (6)
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0b00100000, // '
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0b00111001, // ( ([)
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0b00001111, // )
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0b01110000, // *
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0b01000110, // +
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0b00010000, // ,
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0b01000000, // -
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0b00010000, // . (,)
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0b01010010, // /
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0b00111111, // 0
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0b00000110, // 1
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0b01011011, // 2
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0b01001111, // 3
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0b01100110, // 4
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0b01101101, // 5
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0b01111101, // 6
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0b00000111, // 7
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0b01111111, // 8
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0b01101111, // 9
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0b01001000, // : (=)
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0b01001000, // ; (=)
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0b01011000, // <
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0b01001000, // =
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0b01001100, // >
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0b01010011, // ?
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0b01111011, // @
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0b01110111, // A
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0b01111111, // B
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0b00111001, // C
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0b01011110, // D
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0b01111001, // E
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0b01110001, // F
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0b00111101, // G
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0b01110110, // H
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0b00110000, // I
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0b00011110, // J
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0b01110110, // K
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0b00111000, // L
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0b00110111, // M
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0b00110111, // N
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0b00111111, // O
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0b01110011, // P
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0b01101011, // Q
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0b00110011, // R
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0b01101101, // S
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0b01111000, // T
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0b00111110, // U
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0b00111110, // V (U)
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0b00111110, // W (U)
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0b01110110, // X (H)
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0b01101110, // Y
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0b01011011, // Z
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0b00111001, // [
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0b01100100, // '\'
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0b00001111, // /
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0b00100011, // ^
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0b00001000, // _
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0b00000010, // `
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0b01011111, // a
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0b01111100, // b
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0b01011000, // c
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0b01011110, // d
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0b01111011, // e
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0b01110001, // f
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0b01101111, // g
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0b01110100, // h
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0b00010000, // i
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0b00001100, // j
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0b01110110, // k
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0b00110000, // l
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0b01010100, // m
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0b01010100, // n
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0b01011100, // o
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0b01110011, // p
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0b01100111, // q
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0b01010000, // r
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0b01101101, // s
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0b01111000, // t
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0b00011100, // u
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0b00011100, // v (u)
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0b00011100, // w (u)
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0b01110110, // x
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0b01101110, // y
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0b01011011, // z
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0b00111001, // { ([)
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0b00110000, // |
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0b00001111, // } ([)
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0b01000000, // ~
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};
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/** font for the 5x7 dot matrix block
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* @details first value is left-most line, LSB is top dot, MSB is not used
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* @note from http://sunge.awardspace.com/glcd-sd/node4.html
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*/
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static const uint8_t font5x7[][5] = {
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{0x00, 0x00, 0x00, 0x00, 0x00}, // (space)
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{0x00, 0x00, 0x5F, 0x00, 0x00}, // !
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{0x00, 0x07, 0x00, 0x07, 0x00}, // "
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{0x14, 0x7F, 0x14, 0x7F, 0x14}, // #
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{0x24, 0x2A, 0x7F, 0x2A, 0x12}, // $
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{0x23, 0x13, 0x08, 0x64, 0x62}, // %
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{0x36, 0x49, 0x55, 0x22, 0x50}, // &
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{0x00, 0x05, 0x03, 0x00, 0x00}, // '
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{0x00, 0x1C, 0x22, 0x41, 0x00}, // (
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{0x00, 0x41, 0x22, 0x1C, 0x00}, // )
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{0x08, 0x2A, 0x1C, 0x2A, 0x08}, // *
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{0x08, 0x08, 0x3E, 0x08, 0x08}, // +
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{0x00, 0x50, 0x30, 0x00, 0x00}, // ,
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{0x08, 0x08, 0x08, 0x08, 0x08}, // -
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{0x00, 0x60, 0x60, 0x00, 0x00}, // .
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{0x20, 0x10, 0x08, 0x04, 0x02}, // /
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{0x3E, 0x51, 0x49, 0x45, 0x3E}, // 0
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{0x00, 0x42, 0x7F, 0x40, 0x00}, // 1
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{0x42, 0x61, 0x51, 0x49, 0x46}, // 2
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{0x21, 0x41, 0x45, 0x4B, 0x31}, // 3
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{0x18, 0x14, 0x12, 0x7F, 0x10}, // 4
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{0x27, 0x45, 0x45, 0x45, 0x39}, // 5
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{0x3C, 0x4A, 0x49, 0x49, 0x30}, // 6
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{0x01, 0x71, 0x09, 0x05, 0x03}, // 7
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{0x36, 0x49, 0x49, 0x49, 0x36}, // 8
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{0x06, 0x49, 0x49, 0x29, 0x1E}, // 9
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{0x00, 0x36, 0x36, 0x00, 0x00}, // :
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{0x00, 0x56, 0x36, 0x00, 0x00}, // ;
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{0x00, 0x08, 0x14, 0x22, 0x41}, // <
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{0x14, 0x14, 0x14, 0x14, 0x14}, // =
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{0x41, 0x22, 0x14, 0x08, 0x00}, // >
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{0x02, 0x01, 0x51, 0x09, 0x06}, // ?
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{0x32, 0x49, 0x79, 0x41, 0x3E}, // @
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{0x7E, 0x11, 0x11, 0x11, 0x7E}, // A
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{0x7F, 0x49, 0x49, 0x49, 0x36}, // B
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{0x3E, 0x41, 0x41, 0x41, 0x22}, // C
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{0x7F, 0x41, 0x41, 0x22, 0x1C}, // D
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{0x7F, 0x49, 0x49, 0x49, 0x41}, // E
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{0x7F, 0x09, 0x09, 0x01, 0x01}, // F
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{0x3E, 0x41, 0x41, 0x51, 0x32}, // G
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{0x7F, 0x08, 0x08, 0x08, 0x7F}, // H
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{0x00, 0x41, 0x7F, 0x41, 0x00}, // I
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{0x20, 0x40, 0x41, 0x3F, 0x01}, // J
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{0x7F, 0x08, 0x14, 0x22, 0x41}, // K
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{0x7F, 0x40, 0x40, 0x40, 0x40}, // L
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{0x7F, 0x02, 0x04, 0x02, 0x7F}, // M
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{0x7F, 0x04, 0x08, 0x10, 0x7F}, // N
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{0x3E, 0x41, 0x41, 0x41, 0x3E}, // O
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{0x7F, 0x09, 0x09, 0x09, 0x06}, // P
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{0x3E, 0x41, 0x51, 0x21, 0x5E}, // Q
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{0x7F, 0x09, 0x19, 0x29, 0x46}, // R
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{0x46, 0x49, 0x49, 0x49, 0x31}, // S
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{0x01, 0x01, 0x7F, 0x01, 0x01}, // T
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{0x3F, 0x40, 0x40, 0x40, 0x3F}, // U
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{0x1F, 0x20, 0x40, 0x20, 0x1F}, // V
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{0x7F, 0x20, 0x18, 0x20, 0x7F}, // W
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{0x63, 0x14, 0x08, 0x14, 0x63}, // X
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{0x03, 0x04, 0x78, 0x04, 0x03}, // Y
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{0x61, 0x51, 0x49, 0x45, 0x43}, // Z
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{0x00, 0x00, 0x7F, 0x41, 0x41}, // [
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{0x02, 0x04, 0x08, 0x10, 0x20}, // '\'
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{0x41, 0x41, 0x7F, 0x00, 0x00}, // ]
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{0x04, 0x02, 0x01, 0x02, 0x04}, // ^
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{0x40, 0x40, 0x40, 0x40, 0x40}, // _
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{0x00, 0x01, 0x02, 0x04, 0x00}, // `
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{0x20, 0x54, 0x54, 0x54, 0x78}, // a
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{0x7F, 0x48, 0x44, 0x44, 0x38}, // b
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{0x38, 0x44, 0x44, 0x44, 0x20}, // c
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{0x38, 0x44, 0x44, 0x48, 0x7F}, // d
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{0x38, 0x54, 0x54, 0x54, 0x18}, // e
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{0x08, 0x7E, 0x09, 0x01, 0x02}, // f
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{0x08, 0x14, 0x54, 0x54, 0x3C}, // g
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{0x7F, 0x08, 0x04, 0x04, 0x78}, // h
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{0x00, 0x44, 0x7D, 0x40, 0x00}, // i
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{0x20, 0x40, 0x44, 0x3D, 0x00}, // j
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{0x00, 0x7F, 0x10, 0x28, 0x44}, // k
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{0x00, 0x41, 0x7F, 0x40, 0x00}, // l
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{0x7C, 0x04, 0x18, 0x04, 0x78}, // m
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{0x7C, 0x08, 0x04, 0x04, 0x78}, // n
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{0x38, 0x44, 0x44, 0x44, 0x38}, // o
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{0x7C, 0x14, 0x14, 0x14, 0x08}, // p
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{0x08, 0x14, 0x14, 0x18, 0x7C}, // q
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{0x7C, 0x08, 0x04, 0x04, 0x08}, // r
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{0x48, 0x54, 0x54, 0x54, 0x20}, // s
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{0x04, 0x3F, 0x44, 0x40, 0x20}, // t
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{0x3C, 0x40, 0x40, 0x20, 0x7C}, // u
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{0x1C, 0x20, 0x40, 0x20, 0x1C}, // v
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{0x3C, 0x40, 0x30, 0x40, 0x3C}, // w
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{0x44, 0x28, 0x10, 0x28, 0x44}, // x
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{0x0C, 0x50, 0x50, 0x50, 0x3C}, // y
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{0x44, 0x64, 0x54, 0x4C, 0x44}, // z
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{0x00, 0x08, 0x36, 0x41, 0x00}, // {
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{0x00, 0x00, 0x7F, 0x00, 0x00}, // |
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{0x00, 0x41, 0x36, 0x08, 0x00}, // }
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{0b00001000, 0b00000100, 0b00001100, 0b00001000, 0b00000100} // ~
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};
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/** pictures for the 5x7 dot matrix block
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* @details first value is left-most line, LSB is top dot, MSB is not used
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*/
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static const uint8_t pict5x7[][5] = {
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{0x08, 0x08, 0x2A, 0x1C, 0x08}, // ->
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{0x08, 0x1C, 0x2A, 0x08, 0x08}, // <-
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{0b01110000, 0b01110000, 0b01111010, 0b01111100, 0b01011000}, // bunny side 1
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{0b00100000, 0b01110000, 0b01110010, 0b01111100, 0b01011000}, // bunny side 2
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{0b00111110, 0b01001001, 0b01010110, 0b01001001, 0b00111110}, // bunny face 1
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{0b00111110, 0b01010001, 0b01100110, 0b01010001, 0b00111110}, // bunny face 2
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{0b00111000, 0b01010111, 0b01100100, 0b01010111, 0b00111000}, // bunny face 3
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{0b00111000, 0b01001111, 0b01010100, 0b01001111, 0b00111000}, // bunny face 4
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{0b00111000, 0b01011110, 0b01101000, 0b01011110, 0b00111000}, // bunny face 5
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{0b01000001, 0b00110110, 0b00001000, 0b00110110, 0b01000001}, // cross 1
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{~0b01000001, ~0b00110110, ~0b00001000, ~0b00110110, ~0b01000001}, // cross 1 negated
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{0b00100010, 0b00010100, 0b00001000, 0b00010100, 0b00100010}, // cross 2
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{~0b00100010, ~0b00010100, ~0b00001000, ~0b00010100, ~0b00100010}, // cross 2 negated
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{0x00, 0x00, 0x00, 0x00, 0x00} // nothing
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};
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/** the 32 bits values to be shifted out to the VFD driver
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* @note split into 16 bit for SPI transfer
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* @note since the bits for digits and matrix are independent, they can be combined
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* @note we have more matrix (12) than digits (10)
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*/
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static uint16_t driver_data[VFD_MATRIX][VFD_DRIVERS*2] = {0};
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/** which driver data is being transmitted */
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static volatile uint8_t spi_i = 0;
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/** which grid/part to activate
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* @note digits and matrix can be combined
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*/
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static volatile uint8_t vfd_grid = 0;
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/** the bits used for selecting then digit and 7 segment anodes
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* @note for the second driver
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*/
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static const uint32_t digit_mask = 0x00fffff0;
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void vfd_digit(uint8_t nb, char c)
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{
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if (!(nb<VFD_DIGITS)) { // check the digit exists
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return;
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}
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uint32_t digit_data = 0; // the data to be shifted out for the driver (for the second driver)
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digit_data = 1<<(4+(9-nb)); // select digit
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/* encode segment
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* here the bit order (classic 7 segment + underline and dot)
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* 3_
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* 8|9_|4
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* 7|6_|5.1
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* 0_2,
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* */
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if (false) { // add the underline (not encoded)
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digit_data |= (1<<(14));
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}
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if (c&0x80) { // add the dot (encoded in the 8th bit)
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digit_data |= (1<<(15));
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}
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if (false) { // add the comma (not encoded)
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digit_data |= (1<<(16));
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}
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c &= 0x7f; // only take the ASCII part
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if (c>=' ') { // only take printable characters
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uint8_t i = c-' '; // get index for character
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if (i<LENGTH(ascii_7segments)) {
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digit_data |= (ascii_7segments[i]<<(17)); // add encoded segments to memory
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}
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}
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digit_data &= digit_mask; // be sure only the bits for the digit are used
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digit_data |= (driver_data[nb][2]+(driver_data[nb][3]<<16))&~digit_mask; // get the existing data and add the bits for the digit
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driver_data[nb][2] = digit_data; // write back data (least significant half)
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driver_data[nb][3] = (digit_data>>16); // write back data (most significant half)
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}
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void vfd_matrix(uint8_t nb, char c)
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{
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// check the matrix exists
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if (!(nb<VFD_MATRIX)) {
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return;
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}
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uint32_t matrix_data[VFD_DRIVERS] = {0}; // the data to be shifted out for the driver
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// select matrix
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if (nb<4) {
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matrix_data[1] = 1<<(3-nb);
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} else {
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matrix_data[0] = 1<<(35-nb);
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}
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if ((c<0x80) && (c>=' ')) { // only take printable characters
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uint8_t i = c-' '; // get index for character
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if (i<LENGTH(font5x7)) {
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matrix_data[1] |= font5x7[i][0]<<24;
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matrix_data[2] |= font5x7[i][1]<<0;
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matrix_data[2] |= font5x7[i][2]<<8;
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matrix_data[2] |= font5x7[i][3]<<16;
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matrix_data[2] |= font5x7[i][4]<<24;
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}
|
|
} 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
|
|
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
|
|
}
|
|
|
|
/** 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
|
|
}
|
|
}
|
|
}
|
|
|
|
/** 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
|
|
}
|
|
}
|