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Copy pathst7920.py
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150 lines (131 loc) · 4.06 KB
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import spidev
import png
from copy import deepcopy
class ST7920:
def __init__(self):
self.spi = spidev.SpiDev()
self.spi.open(0,0)
self.spi.cshigh = False # use inverted CS
self.spi.max_speed_hz = 530000 # set SPI clock to 1.8MHz, up from 125kHz
self.send(0,0,0x30) # basic instruction set
self.send(0,0,0x30) # repeated
self.send(0,0,0x0C) # display on
self.send(0,0,0x34) #enable RE mode
self.send(0,0,0x34)
self.send(0,0,0x36) #enable graphics display
self.set_rotation(0) # rotate to 0 degrees
self.fontsheet = self.load_font_sheet("fontsheet.png", 6, 8)
self.clear()
self.currentlydisplayedfbuff = None
self.redraw()
def set_rotation(self, rot):
if rot==0 or rot==2:
self.width = 128
self.height = 64
elif rot==1 or rot==3:
self.width = 64
self.height = 128
self.rot = rot
def load_font_sheet(self, filename, cw, ch):
img = png.Reader(filename).read()
rows = list(img[2])
height = len(rows)
width = len(rows[0])
sheet = []
for y in range(height//ch):
for x in range(width//cw):
char = []
for sy in range(ch):
row = rows[(y*ch)+sy]
char.append(row[(x*cw):(x+1)*cw])
sheet.append(char)
return (sheet, cw, ch)
def send(self, rs, rw, cmds):
if type(cmds) is int: # if a single arg, convert to a list
cmds = [cmds]
b1 = 0b11111000 | ((rw&0x01)<<2) | ((rs&0x01)<<1)
bytes = []
for cmd in cmds:
bytes.append(cmd & 0xF0)
bytes.append((cmd & 0x0F)<<4)
return self.spi.xfer2([b1] + bytes)
def clear(self):
self.fbuff = [[0]*(128//8) for i in range(64)]
def line(self, x1, y1, x2, y2, set=True):
diffX = abs(x2-x1)
diffY = abs(y2-y1)
shiftX = 1 if (x1 < x2) else -1
shiftY = 1 if (y1 < y2) else -1
err = diffX - diffY
drawn = False
while not drawn:
self.plot(x1, y1, set)
if x1 == x2 and y1 == y2:
drawn = True
continue
err2 = 2 * err
if err2 > -diffY:
err -= diffY
x1 += shiftX
if err2 < diffX:
err += diffX
y1 += shiftY
def fill_rect(self, x1, y1, x2, y2, set=True):
for y in range(y1,y2+1):
self.line(x1,y,x2,y, set)
def rect(self, x1, y1, x2, y2, set=True):
self.line(x1,y1,x2,y1,set)
self.line(x2,y1,x2,y2,set)
self.line(x2,y2,x1,y2,set)
self.line(x1,y2,x1,y1,set)
def plot(self, x, y, set):
if x<0 or x>=self.width or y<0 or y>=self.height:
return
if set:
if self.rot==0:
self.fbuff[y][x//8] |= 1 << (7-(x%8))
elif self.rot==1:
self.fbuff[x][15 - (y//8)] |= 1 << (y%8)
elif self.rot==2:
self.fbuff[63 - y][15-(x//8)] |= 1 << (x%8)
elif self.rot==3:
self.fbuff[63 - x][y//8] |= 1 << (7-(y%8))
else:
if self.rot==0:
self.fbuff[y][x//8] &= ~(1 << (7-(x%8)))
elif self.rot==1:
self.fbuff[x][15 - (y//8)] &= ~(1 << (y%8))
elif self.rot==2:
self.fbuff[63 - y][15-(x//8)] &= ~(1 << (x%8))
elif self.rot==3:
self.fbuff[63 - x][y//8] &= ~(1 << (7-(y%8)))
def put_text(self, s, x, y, invert_px=False):
for c in s:
try:
font, cw, ch = self.fontsheet
char = font[ord(c)]
sy = 0
for row in char:
sx = 0
for px in row:
self.plot(x+sx, y+sy, px != 1 if invert_px else px==1)
sx += 1
sy += 1
except KeyError:
pass
x += cw
def _send_line(self, row, dx1, dx2):
self.send(0,0,[0x80 + row%32, 0x80 + ((dx1//16) + (8 if row>=32 else 0))]) # set address
self.send(1,0,self.fbuff[row][dx1//8:(dx2//8)+1])
def redraw(self, dx1=0, dy1=0, dx2=127, dy2=63, full=False):
if self.currentlydisplayedfbuff == None: # first redraw always affects the complete LCD
for row in range(0, 64):
self._send_line(row, 0, 127)
self.currentlydisplayedfbuff = deepcopy(self.fbuff) # currentlydisplayedfbuff is initialized here
else: # redraw has been called before, since currentlydisplayedfbuff is already initialized
for row in range(dy1, dy2+1):
if full or (self.currentlydisplayedfbuff[row] != self.fbuff[row]): # redraw row if full=True or changes are detected
self._send_line(row, dx1, dx2)
self.currentlydisplayedfbuff[row][dx1//8:(dx2//8)+1] = self.fbuff[row][dx1//8:(dx2//8)+1]
def close(self):
self.spi.close()