display: Move st7920 code to its own module

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 127 insertions, 0 deletions

diff --git a/klippy/extras/display/st7920.py b/klippy/extras/display/st7920.py
new file mode 100644
index 00000000..eebc3428
--- /dev/null
+++ b/klippy/extras/display/st7920.py
@@ -0,0 +1,127 @@
+# Support for ST7920 (128x64 graphics) LCD displays
+#
+# Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import logging
+
+BACKGROUND_PRIORITY_CLOCK = 0x7fffffff00000000
+
+# Spec says 72us, but faster is possible in practice
+ST7920_CMD_DELAY  = .000020
+ST7920_SYNC_DELAY = .000045
+
+class ST7920:
+    char_right_arrow = '\x1a'
+    def __init__(self, config):
+        printer = config.get_printer()
+        # pin config
+        ppins = printer.lookup_object('pins')
+        pins = [ppins.lookup_pin('digital_out', config.get(name + '_pin'))
+                for name in ['cs', 'sclk', 'sid']]
+        mcu = None
+        for pin_params in pins:
+            if mcu is not None and pin_params['chip'] != mcu:
+                raise ppins.error("st7920 all pins must be on same mcu")
+            mcu = pin_params['chip']
+            if pin_params['invert']:
+                raise ppins.error("st7920 can not invert pin")
+        self.pins = [pin_params['pin'] for pin_params in pins]
+        self.mcu = mcu
+        self.oid = self.mcu.create_oid()
+        self.mcu.add_config_object(self)
+        self.send_data_cmd = self.send_cmds_cmd = None
+        self.is_extended = False
+        # framebuffers
+        self.text_framebuffer = (bytearray(' '*64), bytearray('~'*64), 0x80)
+        self.glyph_framebuffer = (bytearray(128), bytearray('~'*128), 0x40)
+        self.graphics_framebuffers = [(bytearray(32), bytearray('~'*32), i)
+                                      for i in range(32)]
+        self.framebuffers = ([self.text_framebuffer, self.glyph_framebuffer]
+                             + self.graphics_framebuffers)
+    def build_config(self):
+        self.mcu.add_config_cmd(
+            "config_st7920 oid=%u cs_pin=%s sclk_pin=%s sid_pin=%s"
+            " sync_delay_ticks=%d cmd_delay_ticks=%d" % (
+                self.oid, self.pins[0], self.pins[1], self.pins[2],
+                self.mcu.seconds_to_clock(ST7920_SYNC_DELAY),
+                self.mcu.seconds_to_clock(ST7920_CMD_DELAY)))
+        cmd_queue = self.mcu.alloc_command_queue()
+        self.send_cmds_cmd = self.mcu.lookup_command(
+            "st7920_send_cmds oid=%c cmds=%*s", cq=cmd_queue)
+        self.send_data_cmd = self.mcu.lookup_command(
+            "st7920_send_data oid=%c data=%*s", cq=cmd_queue)
+    def send(self, cmds, is_data=False, is_extended=False):
+        cmd_type = self.send_cmds_cmd
+        if is_data:
+            cmd_type = self.send_data_cmd
+        elif self.is_extended != is_extended:
+            add_cmd = 0x22
+            if is_extended:
+                add_cmd = 0x26
+            cmds = [add_cmd] + cmds
+            self.is_extended = is_extended
+        cmd_type.send([self.oid, cmds], reqclock=BACKGROUND_PRIORITY_CLOCK)
+        #logging.debug("st7920 %d %s", is_data, repr(cmds))
+    def flush(self):
+        # Find all differences in the framebuffers and send them to the chip
+        for new_data, old_data, fb_id in self.framebuffers:
+            if new_data == old_data:
+                continue
+            # Find the position of all changed bytes in this framebuffer
+            diffs = [[i, 1] for i, (nd, od) in enumerate(zip(new_data, old_data))
+                     if nd != od]
+            # Batch together changes that are close to each other
+            for i in range(len(diffs)-2, -1, -1):
+                pos, count = diffs[i]
+                nextpos, nextcount = diffs[i+1]
+                if pos + 5 >= nextpos and nextcount < 16:
+                    diffs[i][1] = nextcount + (nextpos - pos)
+                    del diffs[i+1]
+            # Transmit changes
+            for pos, count in diffs:
+                count += pos & 0x01
+                count += count & 0x01
+                pos = pos & ~0x01
+                chip_pos = pos >> 1
+                if fb_id < 0x40:
+                    # Graphics framebuffer update
+                    self.send([0x80 + fb_id, 0x80 + chip_pos], is_extended=True)
+                else:
+                    self.send([fb_id + chip_pos])
+                self.send(new_data[pos:pos+count], is_data=True)
+            old_data[:] = new_data
+    def init(self):
+        cmds = [0x24, # Enter extended mode
+                0x40, # Clear vertical scroll address
+                0x02, # Enable CGRAM access
+                0x26, # Enable graphics
+                0x22, # Leave extended mode
+                0x02, # Home the display
+                0x06, # Set positive update direction
+                0x0c] # Enable display and hide cursor
+        self.send(cmds)
+        self.flush()
+    def load_glyph(self, glyph_id, data):
+        if len(data) > 32:
+            data = data[:32]
+        pos = min(glyph_id * 32, 96)
+        self.glyph_framebuffer[0][pos:pos+len(data)] = data
+    def write_text(self, x, y, data):
+        if x + len(data) > 16:
+            data = data[:16 - min(x, 16)]
+        pos = [0, 32, 16, 48][y] + x
+        self.text_framebuffer[0][pos:pos+len(data)] = data
+    def write_graphics(self, x, y, row, data):
+        if x + len(data) > 16:
+            data = data[:16 - min(x, 16)]
+        gfx_fb = y * 16 + row
+        if gfx_fb >= 32:
+            gfx_fb -= 32
+            x += 16
+        self.graphics_framebuffers[gfx_fb][0][x:x+len(data)] = data
+    def clear(self):
+        self.text_framebuffer[0][:] = ' '*64
+        zeros = bytearray(32)
+        for new_data, old_data, fb_id in self.graphics_framebuffers:
+            new_data[:] = zeros