一、目的
这一节我们来学习如何使用合宙ESP32 C3连接控制诺基亚Nokia 5110 LCD 屏幕，实现文字显示。下面我们一起来学习一下吧！
二、环境
ESP32 C3开发板（MicroPython v1.19.1 on 2022-06-18）+ 诺基亚Nokia 5110 LCD 屏幕+ 几根杜邦线 + Win10商业版
ESP32 C3和各模块接线方法：
三、模块介绍
四、屏幕驱动
pcd8544.py
"""
MicroPython Nokia 5110 PCD8544 84x48 LCD driver
"""
from micropython import const
from ustruct import pack
from utime import sleep_us
from machine import Pin,PWM
import framebuf
# Function set 0010 0xxx
FUNCTION_SET = const(0x20)
POWER_DOWN = const(0x04)
ADDRESSING_VERT = const(0x02)
EXTENDED_INSTR = const(0x01)
# Display control 0000 1x0x
DISPLAY_BLANK = const(0x08)
DISPLAY_ALL = const(0x09)
DISPLAY_NORMAL = const(0x0c)
DISPLAY_INVERSE = const(0x0d)
# Temperature control 0000 01xx
TEMP_COEFF_0 = const(0x04)
TEMP_COEFF_1 = const(0x05)
TEMP_COEFF_2 = const(0x06) # default
TEMP_COEFF_3 = const(0x07)
# Bias system 0001 0xxx
BIAS_1_100 = const(0x10)
BIAS_1_80 = const(0x11)
BIAS_1_65 = const(0x12)
BIAS_1_48 = const(0x13)
BIAS_1_40 = const(0x14) # default
BIAS_1_24 = const(0x15)
BIAS_1_18 = const(0x16)
BIAS_1_10 = const(0x17)
# Set operation voltage
SET_VOP = const(0x80)
# DDRAM addresses
COL_ADDR = const(0x80) # x pos (0~83)
BANK_ADDR = const(0x40) # y pos, in banks of 8 rows (0~5)
# Display dimensions
WIDTH = const(0x54) # 84
HEIGHT = const(0x30) # 48
class PCD8544(framebuf.FrameBuffer):
def __init__(self, spi, cs, dc, rst, blk):
self.spi = spi
self.cs = cs # chip enable, active LOW
self.dc = dc # data HIGH, command LOW
self.rst = rst # reset, active LOW
self.blk = PWM(Pin(blk),freq = 1000,duty = 0)#bei guang she zhi
self.height = HEIGHT # For Writer class
self.width = WIDTH
self.cs.init(self.cs.OUT, value=1)
self.dc.init(self.dc.OUT, value=0)
if self.rst:
self.rst.init(self.rst.OUT, value=1)
self.buf = bytearray((HEIGHT // 8) * WIDTH)
super().__init__(self.buf, WIDTH, HEIGHT, framebuf.MONO_VLSB)
self.reset()
self.init()
def init(self, horizontal=True, contrast=0x3f, bias=BIAS_1_40, temp=TEMP_COEFF_2):
# power up, horizontal addressing, basic instruction set
self.fn = FUNCTION_SET
self.addressing(horizontal)
self.contrast(contrast, bias, temp)
self.cmd(DISPLAY_NORMAL)
self.clear()
def reset(self):
# issue reset impulse to reset the display
# you need to call power_on() or init() to resume
self.rst(1)
sleep_us(100)
self.rst(0)
sleep_us(100) # reset impulse has to be >100 ns and <100 ms
self.rst(1)
sleep_us(100)
def power_on(self):
self.cs(1)
self.fn &= ~POWER_DOWN
self.cmd(self.fn)
def power_off(self):
self.fn |= POWER_DOWN
self.cmd(self.fn)
def contrast(self, contrast=0x3f, bias=BIAS_1_40, temp=TEMP_COEFF_2):
for cmd in (
# extended instruction set is required to set temp, bias and vop
self.fn | EXTENDED_INSTR,
# set temperature coefficient
temp,
# set bias system (n=3 recommended mux rate 1:40/1:34)
bias,
# set contrast with operating voltage (0x00~0x7f)
# 0x00 = 3.00V, 0x3f = 6.84V, 0x7f = 10.68V
# starting at 3.06V, each bit increments voltage by 0.06V at room temperature
SET_VOP | contrast,
# revert to basic instruction set
self.fn & ~EXTENDED_INSTR):
self.cmd(cmd)
def invert(self, invert):
self.cmd(DISPLAY_INVERSE if invert else DISPLAY_NORMAL)
def clear(self):
# clear DDRAM, reset x,y position to 0,0
self.data([0] * (HEIGHT * WIDTH // 8))
self.position(0, 0)
def addressing(self, horizontal=True):
# vertical or horizontal addressing
if horizontal:
self.fn &= ~ADDRESSING_VERT
else:
self.fn |= ADDRESSING_VERT
self.cmd(self.fn)
def position(self, x, y):
# set cursor to column x (0~83), bank y (0~5)
self.cmd(COL_ADDR | x) # set x pos (0~83)
self.cmd(BANK_ADDR | y) # set y pos (0~5)
def cmd(self, command):
self.dc(0)
self.cs(0)
self.spi.write(bytearray([command]))
self.cs(1)
def data(self, data):
self.dc(1)
self.cs(0)
self.spi.write(pack('B'*len(data), *data))
self.cs(1)
def show(self):
self.data(self.buf)
def Blk(self,BLK):
self.blk.duty(int((BLK/1000)*1023))
五、字库文件
1，字体文件unifont-14.0.04.bmf从这篇文章的第五节，某度网盘下载：
物联网开发125 - Micropython ESP32 C3 NecIR VS1838B红外遥控解码+ST7735S屏显示-CSDN博客
2，字库ufont.py
__version__ = 3
import time
import struct
import framebuf
DEBUG = False
def timeit(f, *args, **kwargs):
try:
myname = str(f).split(' ')[1]
except:
myname = "UNKONW"
def new_func(*args, **kwargs):
if DEBUG:
try:
t = time.ticks_us()
result = f(*args, **kwargs)
delta = time.ticks_diff(time.ticks_us(), t)
print('Function {} Time = {:6.3f}ms'.format(myname, delta / 1000))
except AttributeError:
t = time.perf_counter_ns()
result = f(*args, **kwargs)
delta = time.perf_counter_ns() - t
print('Function {} Time = {:6.3f}ms'.format(myname, delta / 1000000))
return result
else:
return f(*args, **kwargs)
return new_func
class BMFont:
@staticmethod
def _list_to_byte(arr):
b = 0
for a in arr:
b = (b << 1) + a
return bytes([b])
@timeit
def _bit_list_to_byte_data(self, bit_list):
"""将点阵转换为字节数据
Args:
bit_list:
Returns:
"""
byte_data = b''
for _col in bit_list:
for i in range(0, len(_col), 8):
byte_data += self._list_to_byte(_col[i:i + 8])
return byte_data
@timeit
def __init__(self, font_file):
self.font_file = font_file
self.font = open(font_file, "rb", buffering=0xff)
self.bmf_info = self.font.read(16)
if self.bmf_info[0:2] != b"BM":
raise TypeError("字体文件格式不正确: " + font_file)
self.version = self.bmf_info[2]
if self.version != 3:
raise TypeError("字体文件版本不正确: " + str(self.version))
self.map_mode = self.bmf_info[3] # 映射方式
self.start_bitmap = struct.unpack(">I", b'\x00' + self.bmf_info[4:7])[0] # 位图开始字节
self.font_size = self.bmf_info[7] # 字体大小
self.bitmap_size = self.bmf_info[8] # 点阵所占字节
@timeit
def _to_bit_list(self, byte_data, font_size, *, _height=None, _width=None):
"""将字节数据转换为点阵数据
Args:
byte_data: 字节数据
font_size: 字号大小
_height: 字体原高度
_width: 字体原宽度
Returns:
"""
_height = _height or self.font_size
_width = _width or self.bitmap_size // self.font_size * 8
new_bitarray = [[0 for j in range(font_size)] for i in range(font_size)]
for _col in range(len(new_bitarray)):
for _row in range(len(new_bitarray[_col])):
_index = int(_col / (font_size / _height)) * _width + int(_row / (font_size / _width))
new_bitarray[_col][_row] = byte_data[_index // 8] >> (7 - _index % 8) & 1
return new_bitarray
@timeit
def _color_render(self, bit_list, color):
"""将二值点阵图像转换为 RGB565 彩色字节图像
Args:
bit_list:
color:
Returns:
"""
color_array = b""
for _col in range(len(bit_list)):
for _row in range(len(bit_list)):
color_array += struct.pack("<H", color) if bit_list[_col][_row] else b'\x00\x00'
return color_array
@timeit
def _get_index(self, word):
"""获取索引
Args:
word: 字符
Returns:
"""
word_code = ord(word)
start = 0x10
end = self.start_bitmap
while start <= end:
mid = ((start + end) // 4) * 2
self.font.seek(mid, 0)
target_code = struct.unpack(">H", self.font.read(2))[0]
if word_code == target_code:
return (mid - 16) >> 1
elif word_code < target_code:
end = mid - 2
else:
start = mid + 2
return -1
@timeit
def get_bitmap(self, word):
"""获取点阵图
Args:
word: 字符
Returns:
bytes 字符点阵
"""
index = self._get_index(word)
if index == -1:
return b'\xff\xff\xff\xff\xff\xff\xff\xff\xf0\x0f\xcf\xf3\xcf\xf3\xff\xf3\xff\xcf\xff?\xff?\xff\xff\xff' \
b'?\xff?\xff\xff\xff\xff'
self.font.seek(self.start_bitmap + index * self.bitmap_size, 0)
return self.font.read(self.bitmap_size)
@timeit
def text(self, display, string, x, y, color=1, *, font_size=None, reverse=False, clear=False, show=False,
half_char=True, auto_wrap=False, **kwargs):
"""通过显示屏显示文字
使用此函数显示文字，必须先确认显示对象是否继承与 framebuf.FrameBuffer。
如果显示对象没有 clear 方法，需要自行调用 fill 清屏
Args:
display: 显示实例
string: 字符串
x: 字体左上角 x 轴
y: 字体左上角 y 轴
color: 颜色
font_size: 字号
reverse: 是否反转背景
clear: 是否清除之前显示的内容
show: 是否立刻显示
half_char: 是否半字节显示 ASCII 字符
auto_wrap: 自动换行
**kwargs:
Returns:
None
"""
font_size = font_size or self.font_size
initial_x = x
# 清屏
try:
display.clear() if clear else 0
except AttributeError:
print("请自行调用 display.fill(*) 清屏")
for char in range(len(string)):
# 是否自动换行
if auto_wrap:
if auto_wrap and ((x + font_size // 2 >= 128 and ord(string[char]) < 128 and half_char) or
(x + font_size >= 128 and (not half_char or ord(string[char]) > 128))):
y += font_size
x = initial_x
# 回车
if string[char] == '\n':
y += font_size
x = initial_x
continue
# Tab
elif string[char] == '\t':
x = ((x // font_size) + 1) * font_size + initial_x % font_size
continue
# 其它的控制字符不显示
elif ord(string[char]) < 16:
continue
# 超过范围的字符不会显示*
if x > 160 or y > 80:
continue
byte_data = list(self.get_bitmap(string[char]))
# 反转
if reverse:
for _pixel in range(len(byte_data)):
byte_data[_pixel] = ~byte_data[_pixel] & 0xff
# 缩放和色彩*
if color > 1 or font_size != self.font_size:
bit_data = self._to_bit_list(byte_data, font_size)
if color > 1:
display.blit(
framebuf.FrameBuffer(bytearray(self._color_render(bit_data, color)), font_size, font_size,
framebuf.RGB565), x, y)
else:
display.blit(
framebuf.FrameBuffer(bytearray(self._bit_list_to_byte_data(bit_data)), font_size, font_size,
framebuf.MONO_HLSB), x, y)
else:
display.blit(framebuf.FrameBuffer(bytearray(byte_data), font_size, font_size, framebuf.MONO_HLSB), x, y)
# 英文字符半格显示
if ord(string[char]) < 128 and half_char:
x += font_size // 2
else:
x += font_size
display.show() if show else 0
def char(self, char, color=1, font_size=None, reverse=False):
""" 获取字体字节数据
在没有继承 framebuf.FrameBuffer 的显示驱动,或者内存不足以将一整个屏幕载入缓存帧时
可以直接获取单字的字节数据,局部更新
Args:
char: 单个字符
color: 颜色
font_size: 字体大小
reverse: 反转
Returns:
bytearray
"""
font_size = font_size or self.font_size
byte_data = list(self.get_bitmap(char))
# 反转
if reverse:
for _pixel in range(len(byte_data)):
byte_data[_pixel] = ~byte_data[_pixel] & 0xff
if color > 1 or font_size != self.font_size:
bit_data = self._to_bit_list(byte_data, font_size)
if color > 1:
return self._color_render(bit_data, color)
else:
return self._bit_list_to_byte_data(bit_data)
else:
return bytearray(byte_data)
六、示例程序
demo.py
from machine import Pin,SPI
import time
from pcd8544 import PCD8544
from ufont import BMFont
font = BMFont("unifont-14.0.04.bmf")
spi = SPI(1,baudrate = 1_000_000,polarity = 0,sck = Pin(2),mosi = Pin(3),miso = None)
lcd = PCD8544(spi, cs = Pin(7), dc = Pin(10), rst = Pin(6), blk = 8)
def main():
lcd.Blk(100)
lcd.text("Nokia",0,0,1)
lcd.show()
lcd.hline(0,10,84,1)
lcd.show()
font.text(lcd,"计数",0,20,color=1,font_size=16,reverse=False,clear=False,show=True,half_char=True,auto_wrap=False)
while True:
for i in range(0,100,1):
font.text(lcd,"Num:%.2d"%(i),35,20,color=1,font_size=16,reverse=False,clear=False,show=True,half_char=True,auto_wrap=False)
time.sleep(0.1)
if __name__ == "__main__":
main()
显示效果：
七、模块购买
某宝上有很多，我使用的是这款：
蓝色单片机开发板用 5110液晶屏模块 兼容3310 蓝色背光LCD屏
商品详情
