123 lines
5.1 KiB
Python
123 lines
5.1 KiB
Python
# Support for HD44780 (20x4 text) LCD displays
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#
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# Copyright (C) 2018 Kevin O'Connor <kevin@koconnor.net>
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# Copyright (C) 2018 Eric Callahan <arksine.code@gmail.com>
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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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BACKGROUND_PRIORITY_CLOCK = 0x7fffffff00000000
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TextGlyphs = { 'right_arrow': '\x7e' }
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HD44780_DELAY = .000040
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class HD44780:
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def __init__(self, config):
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self.printer = config.get_printer()
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# pin config
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ppins = self.printer.lookup_object('pins')
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pins = [ppins.lookup_pin(config.get(name + '_pin'))
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for name in ['rs', 'e', 'd4', 'd5', 'd6', 'd7']]
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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("hd44780 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.icons = {}
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# framebuffers
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self.text_framebuffers = [bytearray(' '*40), bytearray(' '*40)]
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self.glyph_framebuffer = bytearray(64)
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self.all_framebuffers = [
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# Text framebuffers
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(self.text_framebuffers[0], bytearray('~'*40), 0x80),
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(self.text_framebuffers[1], bytearray('~'*40), 0xc0),
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# Glyph framebuffer
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(self.glyph_framebuffer, bytearray('~'*64), 0x40) ]
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def build_config(self):
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self.mcu.add_config_cmd(
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"config_hd44780 oid=%d rs_pin=%s e_pin=%s"
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" d4_pin=%s d5_pin=%s d6_pin=%s d7_pin=%s delay_ticks=%d" % (
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self.oid, self.pins[0], self.pins[1],
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self.pins[2], self.pins[3], self.pins[4], self.pins[5],
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self.mcu.seconds_to_clock(HD44780_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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"hd44780_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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"hd44780_send_data oid=%c data=%*s", cq=cmd_queue)
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def send(self, cmds, is_data=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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cmd_type.send([self.oid, cmds], reqclock=BACKGROUND_PRIORITY_CLOCK)
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#logging.debug("hd44780 %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, (n, o) in enumerate(zip(new_data, old_data))
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if n != o]
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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 + 4 >= 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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chip_pos = pos
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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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curtime = self.printer.get_reactor().monotonic()
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print_time = self.mcu.estimated_print_time(curtime)
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# Program 4bit / 2-line mode and then issue 0x02 "Home" command
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init = [[0x33], [0x33], [0x33, 0x22, 0x28, 0x02]]
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# Reset (set positive direction ; enable display and hide cursor)
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init.append([0x06, 0x0c])
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for i, cmds in enumerate(init):
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minclock = self.mcu.print_time_to_clock(print_time + i * .100)
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self.send_cmds_cmd.send([self.oid, cmds], minclock=minclock)
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self.flush()
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def write_text(self, x, y, data):
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if x + len(data) > 20:
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data = data[:20 - min(x, 20)]
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pos = x + ((y & 0x02) >> 1) * 20
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self.text_framebuffers[y & 1][pos:pos+len(data)] = data
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def set_glyphs(self, glyphs):
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for glyph_name, glyph_data in glyphs.items():
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data = glyph_data.get('icon5x8')
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if data is not None:
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self.icons[glyph_name] = data
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def write_glyph(self, x, y, glyph_name):
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data = self.icons.get(glyph_name)
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if data is not None:
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slot, bits = data
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self.write_text(x, y, [slot])
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self.glyph_framebuffer[slot * 8:(slot + 1) * 8] = bits
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return 1
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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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return 0
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def write_graphics(self, x, y, data):
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pass
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def clear(self):
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spaces = ' ' * 40
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self.text_framebuffers[0][:] = spaces
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self.text_framebuffers[1][:] = spaces
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def get_dimensions(self):
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return (20, 4)
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