Merge pull request #47 from jepler/example-updates-background

enhance examples

Author: jepler

examples/pioasm_7seg.py

@@ -0,0 +1,178 @@
+# SPDX-FileCopyrightText: 2022 Jeff Epler, written for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+
+"""Drive a 7-segment display entirely from the PIO peripheral
+
+By updating the buffer being written to the display, the shown digits can be changed.
+
+The main program repeatedly shows random digits which 'lock' after a short
+time. After all digits have locked, it blanks for a short time and then repeats.
+It also demonstrates the use of `asyncio` to perform multiple tasks.
+
+This example is designed for a Raspberry Pi Pico and bare LED display. For
+simplicity, it is wired without any current limiting resistors, instead relying
+on a combination of the RP2040's pin drive strength and the 1/4 duty cycle to
+limit LED current to an acceptable level, and longevity of the display was not
+a priority.
+
+Before integrating a variant of this example code in a project, evaluate
+whether your design needs to add current-limiting resistors.
+
+https://www.adafruit.com/product/4864
+https://www.adafruit.com/product/865
+
+Wiring:
+ * Pico GP15 to LED matrix 1 (E SEG)
+ * Pico GP14 to LED matrix 2 (D SEG)
+ * Pico GP13 to LED matrix 3 (DP SEG)
+ * Pico GP12 to LED matrix 4 (C SEG)
+ * Pico GP11 to LED matrix 5 (G SEG)
+ * Pico GP10 to LED matrix 6 (COM4)
+ * Pico GP9 to LED matrix 7 (COLON COM)
+ * Pico GP22 to LED matrix 8 (COLON SEG)
+ * Pico GP21 to LED matrix 9 (B SEG)
+ * Pico GP20 to LED matrix 10 (COM3)
+ * Pico GP19 to LED matrix 11 (COM2)
+ * Pico GP18 to LED matrix 12 (F SEG)
+ * Pico GP17 to LED matrix 13 (A SEG)
+ * Pico GP16 to LED matrix 14 (COM1)
+"""
+
+import asyncio
+import random
+import array
+import board
+import rp2pio
+import adafruit_pioasm
+
+_program = adafruit_pioasm.Program(
+    """
+    out pins, 14       ; set the pins to their new state
+    """
+)
+
+# Display Pins 1-7 are GP 15-9
+# Display Pins 8-12 are GP 22-16
+COM1_WT = 1 << 7
+COM2_WT = 1 << 10
+COM3_WT = 1 << 11
+COM4_WT = 1 << 1
+COMC_WT = 1 << 0
+
+SEGA_WT = 1 << 8
+SEGB_WT = 1 << 12
+SEGC_WT = 1 << 3
+SEGD_WT = 1 << 5
+SEGE_WT = 1 << 6
+SEGF_WT = 1 << 9
+SEGG_WT = 1 << 2
+
+SEGDP_WT = 1 << 4
+SEGCOL_WT = 1 << 13
+
+ALL_COM = COM1_WT | COM2_WT | COM3_WT | COM4_WT | COMC_WT
+
+SEG_WT = [
+    SEGA_WT,
+    SEGB_WT,
+    SEGC_WT,
+    SEGD_WT,
+    SEGE_WT,
+    SEGF_WT,
+    SEGG_WT,
+    SEGDP_WT,
+    SEGCOL_WT,
+]
+COM_WT = [COM1_WT, COM2_WT, COM3_WT, COM4_WT, COMC_WT]
+
+DIGITS = [
+    0b0111111,  # 0
+    0b0000110,  # 1
+    0b1011011,  # 2
+    0b1001111,  # 3
+    0b1100110,  # 4
+    0b1101101,  # 5
+    0b1111100,  # 6
+    0b0000111,  # 7
+    0b1111111,  # 8
+    0b1101111,  # 9
+]
+
+
+def make_digit_wt(v):
+    val = ALL_COM
+    seg = DIGITS[v]
+    for i in range(8):
+        if seg & (1 << i):
+            val |= SEG_WT[i]
+    return val
+
+
+DIGITS_WT = [make_digit_wt(i) for i in range(10)]
+
+
+class SMSevenSegment:
+    def __init__(self, first_pin=board.GP9):
+        self._buf = array.array("H", (DIGITS_WT[0] & ~COM_WT[i] for i in range(4)))
+        self._sm = rp2pio.StateMachine(
+            _program.assembled,
+            frequency=2000,
+            first_out_pin=first_pin,
+            out_pin_count=14,
+            auto_pull=True,
+            pull_threshold=14,
+            **_program.pio_kwargs,
+        )
+        self._sm.background_write(loop=self._buf)
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.deinit()
+
+    def deinit(self):
+        self._sm.deinit()
+
+    def __setitem__(self, i, v):
+        if v is None:
+            self._buf[i] = 0
+        else:
+            self._buf[i] = DIGITS_WT[v] & ~COM_WT[i]
+
+
+async def digit_locker(s, i, wait):
+    delay = 30
+    d = random.randint(0, 9)
+    while delay < 300:
+        d = (d + random.randint(1, 9)) % 10  # Tick to a new digit other than 'd'
+        s[i] = d
+        await asyncio.sleep(delay / 1000)
+        if wait:
+            wait -= 1
+        else:
+            delay = delay * 1.1
+
+
+def shuffle(seq):
+    for i in range(len(seq) - 1):
+        j = random.randrange(i + 1, len(seq))
+        seq[i], seq[j] = seq[j], seq[i]
+
+
+async def main():
+    waits = [100, 175, 225, 250]
+    with SMSevenSegment(board.GP9) as s:
+        while True:
+            shuffle(waits)
+            await asyncio.gather(
+                *(digit_locker(s, i, di) for i, di in enumerate(waits))
+            )
+            await asyncio.sleep(1)
+            for i in range(4):
+                s[i] = None
+            await asyncio.sleep(0.5)
+
+
+asyncio.run(main())