319 lines
13 KiB
C
319 lines
13 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 communicate with a Titan Micro TM1637 IC attached to a 7-segment displays (code)
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* @file led_tm1637.c
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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* @note peripherals used: GPIO @ref led_tm1637_gpio, timer @ref led_tm1637_timer
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* @note only 4-digit 7-segment displays are considered as this is the most common case
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* @warning all calls are blocking
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* @note the protocol is very similar to I2C but incompatible for the following reasons: the pin capacitance is too large for open-drain type output with weak pull-up resistors (push-pull needs to be used, preventing to get ACKs since no indication of the ACK timing is provided); the devices doesn't use addresses; the STM32 I2C will switch to receiver mode when the first sent byte (the I2C address) has last bit set to 1 (such as for address commands with B7=1 where B7 is transmitted last), preventing to send further bytes (the data byte after the address)
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*
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* bit vs segment: 0bpgfedcba
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* +a+
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* f b p
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* +g+
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* e c p
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* +d+
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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> // memory utilities
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#include <string.h> // string utilities
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/* STM32 (including CM3) libraries */
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#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
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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/timer.h> // timer library
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#include "global.h" // global utilities
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#include "led_tm1637.h" // TM1637 header and definitions
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/** @defgroup led_tm1637_gpio GPIO used to communication with TM1637 IC
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* @{
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*/
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#define LED_TM1637_CLK_PORT B /**< port for CLK signal */
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#define LED_TM1637_CLK_PIN 6 /**< pin for CLK signal */
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#define LED_TM1637_DIO_PORT B /**< port for DIO signal */
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#define LED_TM1637_DIO_PIN 7 /**< pin for DIO signal */
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/** @} */
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/** @defgroup led_tm1637_timer timer used to communication with TM1637 IC
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* @{
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*/
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#define LED_TM1637_TIMER 3 /**< timer to create signal */
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/** @} */
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/** display brightness */
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enum led_tm1637_brightness_t display_brightness = LED_TM1637_14DIV16;
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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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0x00, // 0b00000000 space
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0x30, // 0b00110000 ! (I)
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0x22, // 0b00100010 "
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0x5c, // 0b01011100 # (o)
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0x6d, // 0b01101101 $ (s)
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0x52, // 0b01010010 % (/)
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0x7d, // 0b01111101 & (6)
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0x20, // 0b00100000 '
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0x39, // 0b00111001 ( ([)
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0x0f, // 0b00001111 )
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0x70, // 0b01110000 *
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0x46, // 0b01000110 +
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0x10, // 0b00010000 ,
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0x40, // 0b01000000 -
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0x10, // 0b00010000 . (,)
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0x52, // 0b01010010 /
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0x3f, // 0b00111111 0
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0x06, // 0b00000110 1
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0x5b, // 0b01011011 2
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0x4f, // 0b01001111 3
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0x66, // 0b01100110 4
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0x6d, // 0b01101101 5
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0x7d, // 0b01111101 6
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0x07, // 0b00000111 7
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0x7f, // 0b01111111 8
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0x6f, // 0b01101111 9
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0x48, // 0b01001000 : (=)
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0x48, // 0b01001000 ; (=)
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0x58, // 0b01011000 <
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0x48, // 0b01001000 =
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0x4c, // 0b01001100 >
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0x53, // 0b01010011 ?
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0x7b, // 0b01111011 @
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0x77, // 0b01110111 A
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0x7f, // 0b01111111 B
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0x39, // 0b00111001 C
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0x5e, // 0b01011110 D
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0x79, // 0b01111001 E
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0x71, // 0b01110001 F
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0x3d, // 0b00111101 G
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0x76, // 0b01110110 H
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0x30, // 0b00110000 I
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0x1e, // 0b00011110 J
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0x76, // 0b01110110 K
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0x38, // 0b00111000 L
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0x37, // 0b00110111 M
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0x37, // 0b00110111 N
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0x3f, // 0b00111111 O
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0x73, // 0b01110011 P
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0x6b, // 0b01101011 Q
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0x33, // 0b00110011 R
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0x6d, // 0b01101101 S
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0x78, // 0b01111000 T
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0x3e, // 0b00111110 U
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0x3e, // 0b00111110 V (U)
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0x3e, // 0b00111110 W (U)
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0x76, // 0b01110110 X (H)
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0x6e, // 0b01101110 Y
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0x5b, // 0b01011011 Z
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0x39, // 0b00111001 [
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0x64, // 0b01100100 '\'
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0x0f, // 0b00001111 /
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0x23, // 0b00100011 ^
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0x08, // 0b00001000 _
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0x02, // 0b00000010 `
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0x5f, // 0b01011111 a
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0x7c, // 0b01111100 b
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0x58, // 0b01011000 c
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0x5e, // 0b01011110 d
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0x7b, // 0b01111011 e
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0x71, // 0b01110001 f
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0x6f, // 0b01101111 g
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0x74, // 0b01110100 h
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0x10, // 0b00010000 i
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0x0c, // 0b00001100 j
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0x76, // 0b01110110 k
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0x30, // 0b00110000 l
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0x54, // 0b01010100 m
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0x54, // 0b01010100 n
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0x5c, // 0b01011100 o
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0x73, // 0b01110011 p
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0x67, // 0b01100111 q
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0x50, // 0b01010000 r
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0x6d, // 0b01101101 s
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0x78, // 0b01111000 t
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0x1c, // 0b00011100 u
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0x1c, // 0b00011100 v (u)
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0x1c, // 0b00011100 w (u)
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0x76, // 0b01110110 x
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0x6e, // 0b01101110 y
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0x5b, // 0b01011011 z
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0x39, // 0b00111001 { ([)
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0x30, // 0b00110000 |
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0x0f, // 0b00001111 } ([)
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0x40, // 0b01000000 ~
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};
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void led_tm1637_setup(void)
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{
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// configure GPIO for CLK and DIO signals
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rcc_periph_clock_enable(RCC_GPIO(LED_TM1637_CLK_PORT)); // enable clock for GPIO peripheral
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gpio_set(GPIO(LED_TM1637_CLK_PORT), GPIO(LED_TM1637_CLK_PIN)); // idle high
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gpio_set_mode(GPIO(LED_TM1637_CLK_PORT), GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(LED_TM1637_CLK_PIN)); // master start the communication (capacitance is to large for open drain), only switch to input for ack from slave
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rcc_periph_clock_enable(RCC_GPIO(LED_TM1637_DIO_PORT)); // enable clock for GPIO peripheral
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gpio_set(GPIO(LED_TM1637_DIO_PORT), GPIO(LED_TM1637_DIO_PIN)); // idle high
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gpio_set_mode(GPIO(LED_TM1637_DIO_PORT), GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(LED_TM1637_DIO_PIN)); // master start the communication (capacitance is to large for open drain), only switch to input for ack from slave
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// first clock then data high also stands for stop condition
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// setup timer to create signal timing (each tick is used for a single GPIO transition)
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rcc_periph_clock_enable(RCC_TIM(LED_TM1637_TIMER)); // enable clock for timer block
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timer_reset(TIM(LED_TM1637_TIMER)); // reset timer state
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timer_set_mode(TIM(LED_TM1637_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
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timer_set_prescaler(TIM(LED_TM1637_TIMER), 0); // don't prescale to get most precise timing ( 1/(72E6/1/(2**16))=0.91 ms > 0.5 us )
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timer_set_period(TIM(LED_TM1637_TIMER), rcc_ahb_frequency/50000/2); // set the clock frequency to 50 kHz (500 kHz is the maximum per datasheet, but 50 kHz is empirically more stable due to the line capacitance of the multiple displays)
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timer_clear_flag(TIM(LED_TM1637_TIMER), TIM_SR_UIF); // clear flag
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timer_update_on_overflow(TIM(LED_TM1637_TIMER)); // only use counter overflow as UEV source (use overflow as start time or timeout)
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}
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/** wait until clock tick (timer overflow) occurred
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*/
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static inline void led_tm1637_tick(void)
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{
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while (!timer_get_flag(TIM(LED_TM1637_TIMER), TIM_SR_UIF)); // wait until counter overflow update event happens
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timer_clear_flag(TIM(LED_TM1637_TIMER), TIM_SR_UIF); // clear event flag
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}
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/** write data on bus
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* @param[in] data bytes to write
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* @param[in] length number of bytes to write
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* @return if write succeeded
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* @note includes start and stop conditions
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*/
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static bool led_tm1637_write(const uint8_t* data, uint8_t length)
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{
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bool to_return = true; // return if write succeeded
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if (NULL==data || 0==length) { // verify there it data to be read
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return false;
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}
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// enable timer for signal generation
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gpio_set_mode(GPIO(LED_TM1637_DIO_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(LED_TM1637_DIO_PIN)); // ensure we can output to sent start condition
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timer_set_counter(TIM(LED_TM1637_TIMER), 0); // reset timer counter
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timer_enable_counter(TIM(LED_TM1637_TIMER)); // enable timer to generate timing
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led_tm1637_tick(); // wait to enforce minimum time since last write
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// send start condition (DIO then CLK low)
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gpio_clear(GPIO(LED_TM1637_DIO_PORT), GPIO(LED_TM1637_DIO_PIN)); // put DIO low
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led_tm1637_tick(); // wait for next tick
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gpio_clear(GPIO(LED_TM1637_CLK_PORT), GPIO(LED_TM1637_CLK_PIN)); // put CLK low
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// send data bytes (MSb first)
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for (uint8_t i=0; i<length; i++) { // send all bytes
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uint8_t byte = data[i];
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for (uint8_t b=0; b<8; b++) { // send all bits
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if (byte&0x1) { // send a 1
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gpio_set(GPIO(LED_TM1637_DIO_PORT), GPIO(LED_TM1637_DIO_PIN)); // put DIO high
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} else {
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gpio_clear(GPIO(LED_TM1637_DIO_PORT), GPIO(LED_TM1637_DIO_PIN)); // put DIO low
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}
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byte >>= 1; // shift data
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led_tm1637_tick(); // wait for next tick
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gpio_set(GPIO(LED_TM1637_CLK_PORT), GPIO(LED_TM1637_CLK_PIN)); // put CLK high
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led_tm1637_tick(); // wait for next tick (no DIO transition when CLK is high)
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gpio_clear(GPIO(LED_TM1637_CLK_PORT), GPIO(LED_TM1637_CLK_PIN)); // put CLK low
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}
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gpio_set_mode(GPIO(LED_TM1637_DIO_PORT), GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO(LED_TM1637_DIO_PIN)); // switch DIO as input to read ACK
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led_tm1637_tick(); // wait for next tick (when the slave should ACK)
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gpio_set(GPIO(LED_TM1637_CLK_PORT), GPIO(LED_TM1637_CLK_PIN)); // put CLK high
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if (gpio_get(GPIO(LED_TM1637_DIO_PORT), GPIO(LED_TM1637_DIO_PIN))) { // no ACK received
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to_return = false; // remember there was an error
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break; // stop sending bytes
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}
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led_tm1637_tick(); // wait for next tick
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gpio_clear(GPIO(LED_TM1637_CLK_PORT), GPIO(LED_TM1637_CLK_PIN)); // put CLK low
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gpio_set_mode(GPIO(LED_TM1637_DIO_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(LED_TM1637_DIO_PIN)); // switch DIO back to output
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}
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// send stop condition
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led_tm1637_tick(); // wait for next tick
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gpio_set(GPIO(LED_TM1637_CLK_PORT), GPIO(LED_TM1637_CLK_PIN)); // put CLK high
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led_tm1637_tick(); // wait for next tick
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gpio_set(GPIO(LED_TM1637_DIO_PORT), GPIO(LED_TM1637_DIO_PIN)); // put DIO high
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timer_disable_counter(TIM(LED_TM1637_TIMER)); // stop timer since it's not used anymore
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return to_return;
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}
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/** write commands on bus to send data
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* @param[in] address_command data data to send (including address as first byte)
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* @param[in] length length of data
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* @return if send succeeded
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*/
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static bool led_tm1637_send_data(uint8_t* address_command, uint8_t length)
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{
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// sanity check
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if (0==length && NULL==address_command) {
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return false;
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}
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uint8_t data_command[] = { 0x40 }; // data command: write data, automatic address adding, normal
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uint8_t display_command[] = { 0x88+(display_brightness&0x0f) }; // display command: turn display on and set brightness
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if (led_tm1637_write(data_command, LENGTH(data_command)) && led_tm1637_write(address_command, length) && led_tm1637_write(display_command, LENGTH(display_command))) { // send commands
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return true;
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}
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return false;
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}
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bool led_tm1637_off(void)
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{
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// note: while the TM1637 could recognize the display command thanks to the first two bits, we still need to send the data and address command first
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uint8_t data_command[] = { 0x40 }; // data command: write data, automatic address adding, normal
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uint8_t address_command[] = { 0xc0, 0x00, 0x00, 0x00, 0x00 }; // address command: clear all (if bit 7 of byte 4 is set switching off doesn't work correctly, I don't know why)
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uint8_t display_command[] = { 0x80 }; // display command: turn display off (we don't care about the brightness since it's set when turned on)
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if (led_tm1637_write(data_command,LENGTH(data_command)) && led_tm1637_write(address_command, LENGTH(address_command)) && led_tm1637_write(display_command, LENGTH(display_command))) { // send commands
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return true;
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}
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return false;
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}
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void led_tm1637_brightness(enum led_tm1637_brightness_t brightness)
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{
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display_brightness = (brightness&0x0f); // save brightness
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}
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bool led_tm1637_number(uint16_t number)
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{
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uint8_t data[] = { 0xc0, ascii_7segments[((number/1000)%10)+'0'-' '], ascii_7segments[((number/100)%10)+'0'-' '], ascii_7segments[((number/10)%10)+'0'-' '], ascii_7segments[((number/1)%10)+'0'-' '] }; // encode number on 4 digits
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return led_tm1637_send_data(data, LENGTH(data)); // transmit data
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}
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bool led_tm1637_time(uint8_t hours, uint8_t minutes)
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{
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uint8_t data[] = { 0xc0, ascii_7segments[((hours/10)%10)+'0'-' '], ascii_7segments[((hours/1)%10)+'0'-' ']|0x80, ascii_7segments[((minutes/10)%10)+'0'-' '], ascii_7segments[((minutes/1)%10)+'0'-' '] }; // encode time on 4 digits
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return led_tm1637_send_data(data, LENGTH(data)); // transmit data
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}
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bool led_tm1637_text(char* text)
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{
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if (strlen(text)!=4) { // input text should have exactly 4 characters
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return false;
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}
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for (uint8_t i=0; i<4; i++) { // input text should only contain printable character (8th bit is used for dots)
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if ((text[i]&0x7f)<' ' || (text[i]&0x7f)>=' '+LENGTH(ascii_7segments)) {
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return false;
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}
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}
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uint8_t data[] = { 0xc0, ascii_7segments[(text[0]&0x7f)-' ']|(text[0]&0x80), ascii_7segments[(text[1]&0x7f)-' ']|(text[1]&0x80), ascii_7segments[(text[2]&0x7f)-' ']|(text[2]&0x80), ascii_7segments[(text[3]&0x7f)-' ']|(text[3]&0x80) }; // encode text on 7 digits
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return led_tm1637_send_data(data, LENGTH(data)); // transmit data
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}
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