SSD1306 OLED display driver  1.7.17
This library is developed to control SSD1306/SSD1331/SSD1351/IL9163/PCD8554 RGB i2c/spi LED displays
ssd1306_i2c_embedded.c
1 /*
2  MIT License
3 
4  Copyright (c) 2016-2018, Alexey Dynda
5 
6  Permission is hereby granted, free of charge, to any person obtaining a copy
7  of this software and associated documentation files (the "Software"), to deal
8  in the Software without restriction, including without limitation the rights
9  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  copies of the Software, and to permit persons to whom the Software is
11  furnished to do so, subject to the following conditions:
12 
13  The above copyright notice and this permission notice shall be included in all
14  copies or substantial portions of the Software.
15 
16  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22  SOFTWARE.
23 */
24 
25 #include "ssd1306_i2c_embedded.h"
26 #include "intf/ssd1306_interface.h"
27 #include "ssd1306_i2c.h"
28 
29 #include "ssd1306_hal/io.h"
30 
31 #if defined(CONFIG_SOFTWARE_I2C_AVAILABLE) && defined(CONFIG_SOFTWARE_I2C_ENABLE)
32 
39 static uint8_t s_scl = (1<<SSD1306_SCL);
40 static uint8_t s_sda = (1<<SSD1306_SDA);
41 static uint8_t s_sa = SSD1306_SA;
42 
43 #if defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
44  // at 8Mhz each command takes ~ 0.125us
45  #define DDR_REG DDRB
46  #define PORT_REG PORTB
47 #elif defined(__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
48  // For AttinyX4 controllers
49  // at 8Mhz each command takes ~ 0.125us
50  #define DDR_REG DDRA
51  #define PORT_REG PORTA
52 #else // For Atmega
53  // at 16Mhz each command takes ~ 0.0625us
54  #define DDR_REG DDRC
55  #define PORT_REG PORTC
56 #endif
57 
58 
59 #ifndef F_CPU
60  #warning "F_CPU is not defined, there can be I2C issues"
61  #define F_CPU 8000000
62 #endif
63 #define CPU_CYCLE_NS (1000000000/F_CPU)
64 
65 // each delay loop takes 4 cycles: nop(1), dec(1), jnz(2)
66 #define DELAY_LOOP_CYCLES 4
67 #define ssd1306_delay(x) for(uint8_t i2=x; i2>0; i2--){__asm__("nop\n\t");}
68 
72 #define SSD1306_I2C_START_STOP_DELAY 600
73 #define SSD1306_I2C_RISE_TIME 300
74 #define SSD1306_I2C_FALL_TIME 300
75 #define SSD1306_I2C_DATA_HOLD_TIME 300
76 #define SSD1306_I2C_IDLE_TIME 1300
77 #define SSD1306_I2C_CLOCK 2500
78 
79 
80 #define I2C_START_STOP_DELAY ((SSD1306_I2C_START_STOP_DELAY/CPU_CYCLE_NS + DELAY_LOOP_CYCLES/2)/DELAY_LOOP_CYCLES)
81 
82 #define I2C_RISE_TIME ((SSD1306_I2C_RISE_TIME/CPU_CYCLE_NS)/DELAY_LOOP_CYCLES)
83 
84 #define I2C_DATA_HOLD_TIME ((SSD1306_I2C_DATA_HOLD_TIME/CPU_CYCLE_NS + DELAY_LOOP_CYCLES/2)/DELAY_LOOP_CYCLES)
85 
86 #define I2C_IDLE_TIME (((SSD1306_I2C_IDLE_TIME/CPU_CYCLE_NS) + DELAY_LOOP_CYCLES/2)/DELAY_LOOP_CYCLES)
87 
88 #define I2C_HALF_CLOCK (((SSD1306_I2C_CLOCK - SSD1306_I2C_FALL_TIME - SSD1306_I2C_RISE_TIME - SSD1306_I2C_FALL_TIME)/CPU_CYCLE_NS/2 \
89  )/DELAY_LOOP_CYCLES)
90 
91 
92 /* I2C HIGH = PORT as INPUT(0) and PULL-UP ENABLE (1) */
93 //#define DIGITAL_WRITE_HIGH(DREG, PREG, BIT) { DREG &= ~(1 << BIT); PREG |= (1 << BIT); }
94 #define DIGITAL_WRITE_HIGH(DREG, PREG, BIT) { DREG &= ~BIT; PREG |= BIT; }
95 
96 /* I2C LOW = PORT as OUTPUT(1) and OUTPUT LOW (0) */
97 //#define DIGITAL_WRITE_LOW(DREG, PREG, BIT) { DREG |= (1 << BIT); PREG &= ~(1 << BIT); }
98 #define DIGITAL_WRITE_LOW(DREG, PREG, BIT) { DREG |= BIT; PREG &= ~BIT; }
99 
100 static uint8_t oldSREG;
101 static uint8_t interruptsOff = 0;
102 
107 static void ssd1306_i2cSendByte_Embedded(uint8_t data)
108 {
109  uint8_t i;
110  for(i=8; i>0; i--)
111  {
112  if(data & 0x80)
113  DIGITAL_WRITE_HIGH(DDR_REG, PORT_REG, s_sda)
114  else
115  DIGITAL_WRITE_LOW(DDR_REG, PORT_REG, s_sda);
116  data<<=1;
117  ssd1306_delay(I2C_RISE_TIME); // Fall time is the same as rise time
118 
119  DIGITAL_WRITE_HIGH(DDR_REG, PORT_REG, s_scl);
120  ssd1306_delay(I2C_HALF_CLOCK);
121 
122  DIGITAL_WRITE_LOW(DDR_REG, PORT_REG, s_scl);
123  ssd1306_delay(I2C_HALF_CLOCK);
124  }
125  // generating confirmation impulse
126  DIGITAL_WRITE_HIGH(DDR_REG, PORT_REG, s_sda);
127  ssd1306_delay(I2C_RISE_TIME); // Fall time is the same as rise time
128  DIGITAL_WRITE_HIGH(DDR_REG, PORT_REG, s_scl);
129  ssd1306_delay(I2C_HALF_CLOCK);
130  DIGITAL_WRITE_LOW(DDR_REG, PORT_REG, s_scl);
131  ssd1306_delay(I2C_HALF_CLOCK);
132 }
133 
134 static void ssd1306_i2cSendBytes_Embedded(const uint8_t *buffer, uint16_t size)
135 {
136  while (size--)
137  {
138  ssd1306_i2cSendByte_Embedded(*buffer);
139  buffer++;
140  }
141 }
142 
146 static void ssd1306_i2cStart_Embedded(void)
147 {
148  oldSREG = SREG;
149  cli();
150  interruptsOff = 1;
151  DIGITAL_WRITE_LOW(DDR_REG, PORT_REG, s_sda); // Set to LOW
152  ssd1306_delay(I2C_START_STOP_DELAY);
153  DIGITAL_WRITE_LOW(DDR_REG, PORT_REG, s_scl); // Set to LOW
154  ssd1306_delay(I2C_HALF_CLOCK);
155  ssd1306_i2cSendByte_Embedded((s_sa << 1) | 0);
156 }
157 
158 static void ssd1306_i2cStop_Embedded(void)
159 {
160  DIGITAL_WRITE_LOW(DDR_REG, PORT_REG, s_sda); // Set to LOW
161  ssd1306_delay(I2C_RISE_TIME); // Fall time is the same as rise time
162  DIGITAL_WRITE_HIGH(DDR_REG, PORT_REG, s_scl); // Set to HIGH
163  ssd1306_delay(I2C_START_STOP_DELAY);
164  DIGITAL_WRITE_HIGH(DDR_REG, PORT_REG, s_sda); // Set to HIGH
165  ssd1306_delay(I2C_IDLE_TIME);
166  if (interruptsOff)
167  {
168  SREG = oldSREG;
169  interruptsOff = 0;
170  }
171 }
172 
173 static void ssd1306_i2cClose_Embedded()
174 {
175 }
176 
177 void ssd1306_i2cInit_Embedded(int8_t scl, int8_t sda, uint8_t sa)
178 {
179  if (scl>=0) s_scl = (1<<scl);
180  if (sda>=0) s_sda = (1<<sda);
181  if (sa) s_sa = sa;
182  ssd1306_intf.spi = 0;
183  ssd1306_intf.start = ssd1306_i2cStart_Embedded;
184  ssd1306_intf.stop = ssd1306_i2cStop_Embedded;
185  ssd1306_intf.send = ssd1306_i2cSendByte_Embedded;
186  ssd1306_intf.send_buffer = ssd1306_i2cSendBytes_Embedded;
187  ssd1306_intf.close = ssd1306_i2cClose_Embedded;
188 }
189 
190 #endif
void(* send)(uint8_t data)
#define SSD1306_SDA
SDA, Pin 4 on SSD1306 Board.
void(* close)(void)
deinitializes internal resources, allocated for interface.
ssd1306_interface_t ssd1306_intf
#define SSD1306_SA
#define SSD1306_SCL
SCL, Pin 3 on SSD1306 Board.
void ssd1306_i2cInit_Embedded(int8_t scl, int8_t sda, uint8_t sa)
void(* send_buffer)(const uint8_t *buffer, uint16_t size)
Sends bytes to SSD1306 device.