167 lines
6.8 KiB
Python
167 lines
6.8 KiB
Python
# Support for ST7920 (128x64 graphics) LCD displays
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#
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# Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
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#
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# This file may be distributed under the terms of the GNU GPLv3 license.
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import logging
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import icons, font8x14
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BACKGROUND_PRIORITY_CLOCK = 0x7fffffff00000000
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# Spec says 72us, but faster is possible in practice
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ST7920_CMD_DELAY = .000020
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ST7920_SYNC_DELAY = .000045
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TextGlyphs = { 'right_arrow': '\x1a' }
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CharGlyphs = { 'degrees': font8x14.VGA_FONT[0xf8] }
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class ST7920:
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def __init__(self, config):
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printer = config.get_printer()
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# pin config
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ppins = printer.lookup_object('pins')
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pins = [ppins.lookup_pin(config.get(name + '_pin'))
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for name in ['cs', 'sclk', 'sid']]
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mcu = None
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for pin_params in pins:
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if mcu is not None and pin_params['chip'] != mcu:
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raise ppins.error("st7920 all pins must be on same mcu")
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mcu = pin_params['chip']
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self.pins = [pin_params['pin'] for pin_params in pins]
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self.mcu = mcu
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self.oid = self.mcu.create_oid()
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self.mcu.register_config_callback(self.build_config)
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self.send_data_cmd = self.send_cmds_cmd = None
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self.is_extended = False
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# framebuffers
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self.text_framebuffer = bytearray(' '*64)
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self.glyph_framebuffer = bytearray(128)
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self.graphics_framebuffers = [bytearray(32) for i in range(32)]
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self.all_framebuffers = [
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# Text framebuffer
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(self.text_framebuffer, bytearray('~'*64), 0x80),
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# Glyph framebuffer
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(self.glyph_framebuffer, bytearray('~'*128), 0x40),
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# Graphics framebuffers
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] + [(self.graphics_framebuffers[i], bytearray('~'*32), i)
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for i in range(32)]
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self.cached_glyphs = {}
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def build_config(self):
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self.mcu.add_config_cmd(
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"config_st7920 oid=%u cs_pin=%s sclk_pin=%s sid_pin=%s"
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" sync_delay_ticks=%d cmd_delay_ticks=%d" % (
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self.oid, self.pins[0], self.pins[1], self.pins[2],
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self.mcu.seconds_to_clock(ST7920_SYNC_DELAY),
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self.mcu.seconds_to_clock(ST7920_CMD_DELAY)))
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cmd_queue = self.mcu.alloc_command_queue()
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self.send_cmds_cmd = self.mcu.lookup_command(
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"st7920_send_cmds oid=%c cmds=%*s", cq=cmd_queue)
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self.send_data_cmd = self.mcu.lookup_command(
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"st7920_send_data oid=%c data=%*s", cq=cmd_queue)
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def send(self, cmds, is_data=False, is_extended=False):
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cmd_type = self.send_cmds_cmd
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if is_data:
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cmd_type = self.send_data_cmd
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elif self.is_extended != is_extended:
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add_cmd = 0x22
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if is_extended:
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add_cmd = 0x26
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cmds = [add_cmd] + cmds
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self.is_extended = is_extended
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cmd_type.send([self.oid, cmds], reqclock=BACKGROUND_PRIORITY_CLOCK)
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#logging.debug("st7920 %d %s", is_data, repr(cmds))
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def flush(self):
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# Find all differences in the framebuffers and send them to the chip
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for new_data, old_data, fb_id in self.all_framebuffers:
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if new_data == old_data:
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continue
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# Find the position of all changed bytes in this framebuffer
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diffs = [[i, 1] for i, (nd, od) in enumerate(zip(new_data, old_data))
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if nd != od]
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# Batch together changes that are close to each other
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for i in range(len(diffs)-2, -1, -1):
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pos, count = diffs[i]
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nextpos, nextcount = diffs[i+1]
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if pos + 5 >= nextpos and nextcount < 16:
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diffs[i][1] = nextcount + (nextpos - pos)
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del diffs[i+1]
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# Transmit changes
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for pos, count in diffs:
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count += pos & 0x01
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count += count & 0x01
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pos = pos & ~0x01
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chip_pos = pos >> 1
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if fb_id < 0x40:
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# Graphics framebuffer update
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self.send([0x80 + fb_id, 0x80 + chip_pos], is_extended=True)
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else:
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self.send([fb_id + chip_pos])
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self.send(new_data[pos:pos+count], is_data=True)
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old_data[:] = new_data
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def init(self):
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cmds = [0x24, # Enter extended mode
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0x40, # Clear vertical scroll address
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0x02, # Enable CGRAM access
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0x26, # Enable graphics
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0x22, # Leave extended mode
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0x02, # Home the display
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0x06, # Set positive update direction
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0x0c] # Enable display and hide cursor
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self.send(cmds)
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# Setup animated glyphs
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self.cache_glyph('fan1', 0)
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self.cache_glyph('fan2', 1)
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self.cache_glyph('bed_heat1', 2)
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self.cache_glyph('bed_heat2', 3)
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self.flush()
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def cache_glyph(self, glyph_name, glyph_id):
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icon = icons.Icons16x16[glyph_name]
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for i, bits in enumerate(icon):
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pos = glyph_id*32 + i*2
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b1, b2 = (bits >> 8) & 0xff, bits & 0xff
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self.glyph_framebuffer[pos:pos+2] = [b1, b2]
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self.all_framebuffers[1][1][pos:pos+2] = [b1 ^ 1, b2 ^ 1]
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self.cached_glyphs[glyph_name] = (0, glyph_id*2)
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def write_text(self, x, y, data):
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if x + len(data) > 16:
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data = data[:16 - min(x, 16)]
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pos = [0, 32, 16, 48][y] + x
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self.text_framebuffer[pos:pos+len(data)] = data
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def write_graphics(self, x, y, row, data):
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if x + len(data) > 16:
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data = data[:16 - min(x, 16)]
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gfx_fb = y * 16 + row
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if gfx_fb >= 32:
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gfx_fb -= 32
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x += 16
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self.graphics_framebuffers[gfx_fb][x:x+len(data)] = data
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def write_glyph(self, x, y, glyph_name):
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glyph_id = self.cached_glyphs.get(glyph_name)
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if glyph_id is not None and x & 1 == 0:
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# Render cached icon using character generator
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self.write_text(x, y, glyph_id)
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return 2
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icon = icons.Icons16x16.get(glyph_name)
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if icon is not None:
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# Draw icon in graphics mode
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for i, bits in enumerate(icon):
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self.write_graphics(x, y, i, [(bits >> 8) & 0xff, bits & 0xff])
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return 2
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char = TextGlyphs.get(glyph_name)
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if char is not None:
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# Draw character
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self.write_text(x, y, char)
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return 1
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font = CharGlyphs.get(glyph_name)
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if font is not None:
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# Draw single width character
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for i, bits in enumerate(font):
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self.write_graphics(x, y, i, [bits])
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return 1
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return 0
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def clear(self):
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self.text_framebuffer[:] = ' '*64
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zeros = bytearray(32)
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for gfb in self.graphics_framebuffers:
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gfb[:] = zeros
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