/* 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 .
*
*/
/** library to communicate with a Titan Micro TM1637 IC attached to a 4-digit 7-segment
* @file
* @author King Kévin
* @date 2017-2020
* @note peripherals used: GPIO @ref led_tm1637_gpio, timer @ref led_tm1637_timer
* @note the protocol is very similar to I2C but incompatible for the following reasons: the 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)
* @warning all calls are blocking
*
* bit vs segment: 0bpgfedcba
* +a+
* f b p
* +g+
* e c p
* +d+
*/
/* standard libraries */
#include // standard integer types
#include // general utilities
#include // string utilities
/* STM32 (including CM3) libraries */
#include // Cortex M3 utilities
#include // real-time control clock library
#include // general purpose input output library
#include // timer library
#include "global.h" // global utilities
#include "led_tm1637.h" // TM1637 header and definitions
/** @defgroup led_tm1637_gpio GPIO used to communication with TM1637 IC
* @{
*/
#define LED_TM1637_CLK_PIN PB14 /**< pin for CLK signal */
#define LED_TM1637_DIO_PIN PB13 /**< pin for DIO signal */
/** @} */
/** @defgroup led_tm1637_timer timer used to communication with TM1637 IC
* @{
*/
#define LED_TM1637_TIMER 3 /**< timer to create signal */
/** @} */
/** display brightness */
static enum led_tm1637_brightness_t display_brightness = LED_TM1637_14DIV16;
/** if display is on */
static bool display_on = false;
/** ASCII characters encoded for the 7 segments digit block
* @note starts with space
*/
static const uint8_t ascii_7segments[] = {
0x00, // 0b00000000 space
0x30, // 0b00110000 ! (I)
0x22, // 0b00100010 "
0x5c, // 0b01011100 # (o)
0x6d, // 0b01101101 $ (s)
0x52, // 0b01010010 % (/)
0x7d, // 0b01111101 & (6)
0x20, // 0b00100000 '
0x39, // 0b00111001 ( ([)
0x0f, // 0b00001111 )
0x70, // 0b01110000 *
0x46, // 0b01000110 +
0x10, // 0b00010000 ,
0x40, // 0b01000000 -
0x10, // 0b00010000 . (,)
0x52, // 0b01010010 /
0x3f, // 0b00111111 0
0x06, // 0b00000110 1
0x5b, // 0b01011011 2
0x4f, // 0b01001111 3
0x66, // 0b01100110 4
0x6d, // 0b01101101 5
0x7d, // 0b01111101 6
0x07, // 0b00000111 7
0x7f, // 0b01111111 8
0x6f, // 0b01101111 9
0x48, // 0b01001000 : (=)
0x48, // 0b01001000 ; (=)
0x58, // 0b01011000 <
0x48, // 0b01001000 =
0x4c, // 0b01001100 >
0x53, // 0b01010011 ?
0x7b, // 0b01111011 @
0x77, // 0b01110111 A
0x7f, // 0b01111111 B
0x39, // 0b00111001 C
0x5e, // 0b01011110 D
0x79, // 0b01111001 E
0x71, // 0b01110001 F
0x3d, // 0b00111101 G
0x76, // 0b01110110 H
0x30, // 0b00110000 I
0x1e, // 0b00011110 J
0x76, // 0b01110110 K
0x38, // 0b00111000 L
0x37, // 0b00110111 M
0x37, // 0b00110111 N
0x3f, // 0b00111111 O
0x73, // 0b01110011 P
0x6b, // 0b01101011 Q
0x33, // 0b00110011 R
0x6d, // 0b01101101 S
0x78, // 0b01111000 T
0x3e, // 0b00111110 U
0x3e, // 0b00111110 V (U)
0x3e, // 0b00111110 W (U)
0x76, // 0b01110110 X (H)
0x6e, // 0b01101110 Y
0x5b, // 0b01011011 Z
0x39, // 0b00111001 [
0x64, // 0b01100100 '\'
0x0f, // 0b00001111 /
0x23, // 0b00100011 ^
0x08, // 0b00001000 _
0x02, // 0b00000010 `
0x5f, // 0b01011111 a
0x7c, // 0b01111100 b
0x58, // 0b01011000 c
0x5e, // 0b01011110 d
0x7b, // 0b01111011 e
0x71, // 0b01110001 f
0x6f, // 0b01101111 g
0x74, // 0b01110100 h
0x10, // 0b00010000 i
0x0c, // 0b00001100 j
0x76, // 0b01110110 k
0x30, // 0b00110000 l
0x54, // 0b01010100 m
0x54, // 0b01010100 n
0x5c, // 0b01011100 o
0x73, // 0b01110011 p
0x67, // 0b01100111 q
0x50, // 0b01010000 r
0x6d, // 0b01101101 s
0x78, // 0b01111000 t
0x1c, // 0b00011100 u
0x1c, // 0b00011100 v (u)
0x1c, // 0b00011100 w (u)
0x76, // 0b01110110 x
0x6e, // 0b01101110 y
0x5b, // 0b01011011 z
0x39, // 0b00111001 { ([)
0x30, // 0b00110000 |
0x0f, // 0b00001111 } ([)
0x40, // 0b01000000 ~
};
void led_tm1637_setup(void)
{
// configure GPIO for CLK and DIO signals
rcc_periph_clock_enable(GPIO_RCC(LED_TM1637_CLK_PIN)); // enable clock for GPIO peripheral
gpio_set(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // idle high
gpio_set_mode(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO_PIN(LED_TM1637_CLK_PIN)); // master start the communication (capacitance is to large for open drain), only switch to input for ack from slave
rcc_periph_clock_enable(GPIO_RCC(LED_TM1637_DIO_PIN)); // enable clock for GPIO peripheral
gpio_set(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_PIN(LED_TM1637_DIO_PIN)); // idle high
gpio_set_mode(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO_PIN(LED_TM1637_DIO_PIN)); // master start the communication (capacitance is to large for open drain), only switch to input for ack from slave
// first clock then data high also stands for stop condition
// setup timer to create signal timing (each tick is used for a single GPIO transition)
rcc_periph_clock_enable(RCC_TIM(LED_TM1637_TIMER)); // enable clock for timer block
rcc_periph_reset_pulse(RST_TIM(LED_TM1637_TIMER)); // reset timer state
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
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 )
timer_set_period(TIM(LED_TM1637_TIMER), 500); // set the clock frequency (emprical value until the signal starts to look bad)
timer_clear_flag(TIM(LED_TM1637_TIMER), TIM_SR_UIF); // clear flag
timer_update_on_overflow(TIM(LED_TM1637_TIMER)); // only use counter overflow as UEV source (use overflow as start time or timeout)
}
/** wait until clock tick (timer overflow) occurred
*/
static inline void led_tm1637_tick(void)
{
while (!timer_get_flag(TIM(LED_TM1637_TIMER), TIM_SR_UIF)); // wait until counter overflow update event happens
timer_clear_flag(TIM(LED_TM1637_TIMER), TIM_SR_UIF); // clear event flag
}
/** write data on bus
* @param[in] data bytes to write
* @param[in] length number of bytes to write
* @return if write succeeded
* @note includes start and stop conditions
*/
static bool led_tm1637_write(const uint8_t* data, size_t length)
{
bool to_return = true; // return if write succeeded
if (NULL == data || 0 == length) { // verify there it data to be read
return false;
}
// enable timer for signal generation
timer_set_counter(TIM(LED_TM1637_TIMER), 0); // reset timer counter
timer_enable_counter(TIM(LED_TM1637_TIMER)); // enable timer to generate timing
led_tm1637_tick(); // wait to enforce minimum time since last write
// send start condition (DIO then CLK low)
gpio_clear(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_PIN(LED_TM1637_DIO_PIN)); // put DIO low
led_tm1637_tick(); // wait for next tick
gpio_clear(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // put CLK low
// send data bytes (MSb first)
for (size_t i = 0; i < length; i++) { // send all bytes
uint8_t byte = data[i];
for (uint8_t b = 0; b < 8; b++) { // send all bits
if (byte & 0x1) { // send a 1
gpio_set(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_PIN(LED_TM1637_DIO_PIN)); // put DIO high
} else {
gpio_clear(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_PIN(LED_TM1637_DIO_PIN)); // put DIO low
}
byte >>= 1; // shift data
led_tm1637_tick(); // wait for next tick
gpio_set(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // put CLK high
led_tm1637_tick(); // wait for next tick (no DIO transition when CLK is high)
gpio_clear(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // put CLK low
}
gpio_set_mode(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO_PIN(LED_TM1637_DIO_PIN)); // switch DIO as input to read ACK
led_tm1637_tick(); // wait for next tick (when the slave should ACK)
gpio_set(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // put CLK high
if (gpio_get(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_PIN(LED_TM1637_DIO_PIN))) { // no ACK received
to_return = false; // remember there was an error
break; // stop sending bytes
}
led_tm1637_tick(); // wait for next tick
gpio_clear(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // put CLK low
gpio_set_mode(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO_PIN(LED_TM1637_DIO_PIN)); // switch DIO back to output to send next byte
}
// send stop condition
gpio_set_mode(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO_PIN(LED_TM1637_DIO_PIN)); // ensure DIO is output (in case no ACK as been received
led_tm1637_tick(); // wait for next tick
gpio_set(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // put CLK high
led_tm1637_tick(); // wait for next tick
gpio_set(GPIO_PORT(LED_TM1637_DIO_PIN), GPIO_PIN(LED_TM1637_DIO_PIN)); // put DIO high
timer_disable_counter(TIM(LED_TM1637_TIMER)); // stop timer since it's not used anymore
return to_return;
}
bool led_tm1637_on(void)
{
uint8_t data[] = { 0x88 + display_brightness }; // command to turn display on (use set brightness)
bool to_return = false; // result to return
if (led_tm1637_write(data, LENGTH(data))) { // send command
display_on = true; // remember display is on
to_return = true; // command succeeded
}
return to_return; // return result
}
bool led_tm1637_off(void)
{
uint8_t data[] = { 0x80 + display_brightness }; // command to turn display off (use set brightness)
if (led_tm1637_write(data, LENGTH(data))) { // send command
display_on = false; // remember display is off
return true; // command succeeded
}
return false; // return result
}
bool led_tm1637_brightness(enum led_tm1637_brightness_t brightness)
{
display_brightness = brightness; // save brightness
if (display_on) { // adjust brightness if display is on
return led_tm1637_on(); // adjust brightness
} else {
return true; // command succeeded
}
return false;
}
bool led_tm1637_number(uint16_t number, bool zero)
{
const uint8_t write_data[] = { 0x40 }; // command: write data, automatic address adding, normal
const uint8_t digits[] = { // digits to display
(number / 1000) % 10,
(number / 100) % 10,
(number / 10) % 10,
(number / 1) % 10,
};
uint8_t data[] = { 0xc0, 0, 0, 0, 0}; // number to be displayed
// convert digits to text to be displayed
if (0 == digits[0] && !zero) {
data[1] = ascii_7segments[' ' - ' '];
} else {
data[1] = ascii_7segments[digits[0] + '0' - ' '];
}
if (0 == digits[0] && 0 == digits[1] && !zero) {
data[2] = ascii_7segments[' ' - ' '];
} else {
data[2] = ascii_7segments[digits[1] + '0' - ' '];
}
if (0 == digits[0] && 0 == digits[1] && 0 == digits[2] && !zero) {
data[3] = ascii_7segments[' ' - ' '];
} else {
data[3] = ascii_7segments[digits[2] + '0' - ' '];
}
data[4] = ascii_7segments[digits[3] + '0' - ' '];
// display number
return led_tm1637_write(write_data, LENGTH(write_data)) && led_tm1637_write(data, LENGTH(data)); // send commands
}
bool led_tm1637_time(uint8_t hours, uint8_t minutes)
{
uint8_t write_data[] = { 0x40 }; // command: write data, automatic address adding, normal
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' - ' '] }; // set address C0H and add data
if (led_tm1637_write(write_data, LENGTH(write_data)) && led_tm1637_write(data, LENGTH(data))) { // send commands
return true;
}
return false;
}
bool led_tm1637_text(char* text)
{
if (strlen(text) != 4) { // input text should have exactly 4 characters
return false;
}
for (uint8_t i = 0; i < 4; i++) { // input text should only contain printable character (8th bit is used for dots)
if ((text[i] & 0x7f) < ' ' || (text[i] & 0x7f) >= ' ' + LENGTH(ascii_7segments)) {
return false;
}
}
uint8_t write_data[] = { 0x40 }; // command: write data, automatic address adding, normal
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) }; // set address C0H and add data
if (led_tm1637_write(write_data, LENGTH(write_data)) && led_tm1637_write(data, LENGTH(data))) { // send commands
return true;
}
return false;
}