Chapter 6 code

ch-6/3-change-conditions/pio_one_encoder_when_changed.py

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+"""Send this code, run and watch the repl.
+Then turn the wheel slowly to see the change"""
+import board
+import rp2pio
+import adafruit_pioasm
+import array
+
+program = """
+.program pio_input    
+    set y, 0            ; clear y
+read:
+    mov x, y            ; store old Y in x
+    in null, 32         ; Clear ISR
+    in pins, 2          ; read in two pins (into ISR)
+    mov y, isr          ; store ISR in y
+    jmp x!=y different  ; Jump if its different
+    jmp read            ; otherwise loop back to read
+
+different:
+    push noblock        ; put ISR into input FIFO
+    jmp read            ; loop back
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=20000,
+    first_in_pin=board.GP20,
+    in_pin_count=2
+)
+
+buffer = array.array('I', [0])
+
+while True:
+    sm.readinto(buffer)
+    print("{:032b}".format(buffer[0]))

ch-6/3-change-conditions/pio_two_encoders_when_changed.py

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+"""Send this code, run and watch the repl.
+Then turn the wheel slowly to see the change"""
+import board
+import rp2pio
+import adafruit_pioasm
+import array
+
+program = """
+.program pio_input    
+    set y, 0            ; clear y
+read:
+    mov x, y            ; store old Y in x
+    in null, 31         ; Clear ISR
+    in pins, 2          ; read in two pins (into ISR)
+    mov y, isr          ; store ISR in y
+    jmp x!=y different  ; Jump if its different
+    jmp read            ; otherwise loop back to read
+
+different:
+    push noblock        ; put ISR into input FIFO
+    jmp read            ; loop back
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+left_enc = rp2pio.StateMachine(
+    assembled,
+    frequency=0,
+    first_in_pin=board.GP20,
+    in_pin_count=2
+)
+
+right_enc = rp2pio.StateMachine(
+    assembled,
+    frequency=0,
+    first_in_pin=board.GP26,
+    in_pin_count=2
+) 
+
+buffer = array.array('I', [0])
+
+left_data = 0
+right_data = 0
+
+while True:
+    # read data from the fifo   
+    if left_enc.in_waiting:
+        left_enc.readinto(buffer)
+        left_data = buffer[0]
+        # print it.
+        print("{:08b}   {:08b}".format(left_data, right_data))
+    if right_enc.in_waiting:
+        right_enc.readinto(buffer)
+        right_data = buffer[0]
+        # print it.
+        print("{:08b}   {:08b}".format(left_data, right_data))