Chapter 6 code

ch-6/0-pio-basic/pio_led_test.py

@@ -19,7 +19,7 @@ sm = rp2pio.StateMachine(
 print("real frequency", sm.frequency)
 
 while True:
-    sm.write(bytes((1,)))
+    sm.write(bytes([1]))
     time.sleep(0.5)
-    sm.write(bytes((0,)))
+    sm.write(bytes([0]))
     time.sleep(0.5)

ch-6/1-simple-input/pio_read_1_pin.py

@@ -1,8 +1,10 @@
 """Send this code, run and watch the repl.
 Then turn the wheel slowly to see the change"""
+import time
 import board
 import rp2pio
 import adafruit_pioasm
+import array
 
 pio_input = """
 .program pio_input
@@ -12,17 +14,17 @@ pio_input = """
 
 assembled = adafruit_pioasm.assemble(pio_input)
 
-## set up a statemachine
 sm = rp2pio.StateMachine(
     assembled,
     frequency=2000,
     first_in_pin=board.GP20
 )
 
-buffer = bytearray(1) # an array of bytes to read into - we are just asking for a byte
+buffer = array.array('I', [0])
 
 while True:
     # read data from the fifo
-    data = sm.readinto(buffer)
+    sm.readinto(buffer)
     # print it.
-    print("{:08b}".format(buffer[0]))
+    print(f"{buffer[0]:032b}")
+    time.sleep(0.1)

ch-6/1-simple-input/pio_read_2_pins.py

@@ -3,6 +3,7 @@ Then turn the wheel slowly to see the change"""
 import board
 import rp2pio
 import adafruit_pioasm
+import array
 
 pio_input = """
 .program pio_input
@@ -24,6 +25,6 @@ buffer = bytearray(1) # an array of bytes to read into - we are just asking for
 
 while True:
     # read data from the fifo
-    data = sm.readinto(buffer)
+    sm.readinto(buffer)
     # print it.
     print("{:08b}".format(buffer[0]))

ch-6/2-techniques/debugging_isr.py

@@ -0,0 +1,44 @@
+"""Sometimes, you need to debug a register. 
+ISR is a bit special - when you push, you destroy it's content -
+    you'll need to restore this. If you remove the mov from x, 
+    it is set to 0s.
+It'll cost a few instructions to do."""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = """
+.program debug_register    
+    set y, 21       ; use y to set ISR
+    mov isr, y
+
+; debug isr
+        mov x, isr  ; preserve isr - pushing destroys it
+        push noblock
+        mov isr, x  ; restore isr
+; done debug
+
+; debug isr
+        mov x, isr  ; preserve isr - pushing destroys it
+        push noblock
+        mov isr, x  ; restore isr
+; done debug
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+buffer = array.array('I', [0])
+
+# read the data
+sm.readinto(buffer)
+print("first push: {0} 0b{0:08b} 0x{0:x}".format(buffer[0]))
+
+sm.readinto(buffer)
+print("second:     {0} 0b{0:08b} 0x{0:x}".format(buffer[0]))

ch-6/2-techniques/extract_a_bit.py

@@ -0,0 +1,43 @@
+"""Sometimes we want to extract a specific bit for
+comparison or testing"""
+"""Shifting a register."""
+import rp2pio
+import adafruit_pioasm
+import array
+
+# extracting bit 2
+bit_to_extract = 30
+program = f"""
+.program extract_bit
+    pull block
+
+; print initial state
+    mov isr, osr
+    push noblock    ; and use PUSH to put it on the receive FIFO
+
+; extract - by shifting
+    in osr, {bit_to_extract}  ; get n bits
+    in null, 31  ; keep only 1 bit
+    push noblock
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+
+buffer = array.array('I', [0])
+
+sm.write(array.array('I', [0b01101000_00000000_00000000_00000000]))
+# read the data
+sm.readinto(buffer)
+print("Initial Y: {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+
+sm.readinto(buffer)
+print("Y bit extracted:  {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+
+

ch-6/2-techniques/extract_a_bit_explore.py

@@ -0,0 +1,129 @@
+"""Sometimes we want to extract a specific bit for
+comparison or testing"""
+"""Shifting a register."""
+import rp2pio
+import adafruit_pioasm
+import array
+
+def scenario(test_data, bit_to_extract, expected):
+    program = f"""
+    .program extract_bit    
+        set y, {test_data}    ; set a value in y
+
+    ; extract - by shifting
+        in null, 32     ; clear the isr
+        in y, {bit_to_extract + 1}         ; get n bits
+
+; debug isr
+        mov x, isr  ; preserve isr - pushing destroys it
+        push noblock
+        mov isr, x  ; restore isr
+; done debug
+
+        in null, 31  ; Shift off all but last bit (leaving it)
+
+; debug isr        
+        mov x, isr  ; preserve isr - pushing destroys it
+        push noblock
+        mov isr, x  ; restore isr
+; done debug
+
+        mov y, isr ; reverse the isr back into y
+
+    ; send y to fifo
+        mov isr, y
+        push noblock    ; and use PUSH to put it on the receive FIFO
+    """
+    assembled = adafruit_pioasm.assemble(program)
+
+    ## set up a statemachine
+    with rp2pio.StateMachine(
+        assembled,
+        frequency=2000,
+    ) as sm:
+        buffer = array.array('I', [0])
+
+        print("source bits: {0} 0b{0:032b} 0x{0:x}".format(test_data))
+        sm.readinto(buffer)
+        print("isr mid: {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+        sm.readinto(buffer)
+        print("isr after shift off: {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+        sm.readinto(buffer)
+        print("Y bit extracted:  {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+        if buffer[0] != expected:
+            print("Didn't get what I expected")
+            print("Y bit expected:  {0} 0b{0:032b} 0x{0:x}".format(expected))
+        print("")
+
+def pull_scenario(test_data, bit_to_extract, expected):
+    program = f"""
+    .program extract_bit_pull    
+        pull   block    ; pull data
+        mov y, osr      
+
+    ; extract - by shifting
+        in null, 32     ; clear the isr
+        in y, {bit_to_extract + 1}         ; get n bits
+
+; debug isr
+        mov x, isr  ; preserve isr - pushing destroys it
+        push noblock
+        mov isr, x  ; restore isr
+; done debug
+
+        in null, 31  ; Shift off all but last bit (leaving it)
+
+; debug isr        
+        mov x, isr  ; preserve isr - pushing destroys it
+        push noblock
+        mov isr, x  ; restore isr
+; done debug
+
+        mov y, isr ; reverse the isr back into y
+
+    ; send y to fifo
+        mov isr, y
+        push noblock    ; and use PUSH to put it on the receive FIFO
+    """
+    assembled = adafruit_pioasm.assemble(program)
+
+    ## set up a statemachine
+    with rp2pio.StateMachine(
+        assembled,
+        frequency=2000,
+    ) as sm:
+        sm.write(array.array('I', [test_data]))
+        buffer = array.array('I', [0])
+
+        print("source bits: {0} 0b{0:032b} 0x{0:x}".format(test_data))
+        sm.readinto(buffer)
+        print("isr mid: {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+        sm.readinto(buffer)
+        print("isr after shift off: {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+        sm.readinto(buffer)
+        print("Y bit extracted:  {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+        if buffer[0] != expected:
+            print("Didn't get what I expected")
+            print("Y bit expected:  {0} 0b{0:032b} 0x{0:x}".format(expected))
+        print("")    
+
+scenario(0b101, 1, 0)
+scenario(0b110, 1, 1)
+scenario(0b010, 1, 1)
+scenario(0b100, 2, 1)
+scenario(0b011, 2, 0)
+scenario(0b1011, 3, 1)
+scenario(0b1010, 3, 1)
+scenario(0b1000, 3, 1)
+scenario(0b0111, 3, 0)
+# bit I want
+#                 v
+pull_scenario(0b10101000_00000000_00000000_00000000, 29, 1)
+pull_scenario(0b11011000_00000000_00000000_00000000, 29, 0)
+#                v
+pull_scenario(0b01011000_00000000_00000000_00000000, 30, 1)
+pull_scenario(0b10111000_00000000_00000000_00000000, 30, 0)
+#               v
+pull_scenario(0b10111000_00000000_00000000_00000000, 31, 1)
+pull_scenario(0b01111000_00000000_00000000_00000000, 31, 0)
+

ch-6/2-techniques/invert_a_register.py

@@ -0,0 +1,37 @@
+"""We can invert the bits of a register."""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = """
+.program invert_register    
+    set y, 21       ; set a value in y
+
+; send it to be printed
+    mov isr, y
+    push noblock    ; and use PUSH to put it on the receive FIFO
+    
+; invert
+    mov isr, ~ y      ; copy and reversed the registe into the ISR
+    ; send it to be printed
+    push noblock    ; and use PUSH to put it on the receive FIFO
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+buffer = array.array('i', [0])
+
+# read the data
+sm.readinto(buffer)
+print("{0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+
+# read the data
+sm.readinto(buffer)
+print("{0} 0b{0:032b} 0x{0:x}".format(buffer[0]))

ch-6/2-techniques/pio_counting_down.py

@@ -0,0 +1,37 @@
+"""Count down"""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = """
+.program counting_down    
+    set y, 21       ; set a value in y
+    ; now send it to be printed
+    mov isr, y
+    push noblock    ; and use PUSH to put it on the receive FIFO
+
+    jmp y--, fake    ; subtract from it
+fake:
+    ; now send it to be printed
+    mov isr, y
+    push noblock    ; and use PUSH to put it on the receive FIFO
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+buffer = array.array('I', [0])
+
+# read the data
+sm.readinto(buffer)
+print("Before {0} 0b{0:08b} 0x{0:x}".format(buffer[0]))
+
+# read the data
+sm.readinto(buffer)
+print("After {0} 0b{0:08b} 0x{0:x}".format(buffer[0]))

ch-6/2-techniques/pio_counting_up.py

@@ -0,0 +1,39 @@
+"""Count down"""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = """
+.program counting_up    
+    set y, 21       ; set a value in y
+    ; now send it to be printed
+    mov isr, y
+    push noblock    ; and use PUSH to put it on the receive FIFO
+    
+    ; Add 1
+    mov y, ~ y      ; invert it
+    jmp y--, fake    ; subtract from it
+fake:
+    mov isr, ~ y
+
+    push noblock    ; and use PUSH to put it on the receive FIFO
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+buffer = array.array('I', [0])
+
+# read the data
+sm.readinto(buffer)
+print("Before {0} 0b{0:08b} 0x{0:x}".format(buffer[0]))
+
+# read the data
+sm.readinto(buffer)
+print("After {0} 0b{0:08b} 0x{0:x}".format(buffer[0]))

ch-6/2-techniques/pio_debugging_registers.py

@@ -0,0 +1,26 @@
+"""Sometimes, you need to debug a register. 
+Note - ISR content is destroyed.
+It'll cost a few instructions to do."""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = """
+.program debug_register    
+    set y, 21       ; set a value in y
+    ; now send it to be printed
+    mov isr, y      ; copy the register you need to dump into the ISR
+    push noblock    ; and use PUSH to put it on the receive FIFO
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(assembled, frequency=2000)
+
+buffer = array.array('I', [0])
+
+# read the data
+sm.readinto(buffer)
+print("{0} 0b{0:08b}".format(buffer[0]))

ch-6/2-techniques/reversing_a_register.py

@@ -0,0 +1,37 @@
+"""We can reverse the content of a register."""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = """
+.program reverse_register    
+    set y, 21       ; set a value in y
+
+; send it to be printed
+    mov isr, y
+    push noblock    ; and use PUSH to put it on the receive FIFO
+
+; reverse it
+    mov isr, :: y      ; copy and reversed the register into the ISR
+; print it
+    push noblock    ; and use PUSH to put it on the receive FIFO
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+buffer = array.array('I', [0])
+
+# read the data
+sm.readinto(buffer)
+print("{0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+
+# read the data
+sm.readinto(buffer)
+print("{0} 0b{0:032b} 0x{0:x}".format(buffer[0]))

ch-6/2-techniques/shift_and_reverse.py

@@ -0,0 +1,40 @@
+"""Shift and reverse"""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = """
+.program debug_register    
+    set y, 2       ; set a value in y
+
+
+; send it to be printed
+    mov isr, y
+    push noblock    ; and use PUSH to put it on the receive FIFO
+
+; shift and reverse
+    in y, 1         ; get bits
+    mov isr, :: isr ; reverse it
+
+; print again
+    push noblock    ; and use PUSH to put it on the receive FIFO
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+buffer = array.array('I', [0])
+
+# read the data
+sm.readinto(buffer)
+print("{0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+
+# read the data
+sm.readinto(buffer)
+print("{0} 0b{0:032b} 0x{0:x}".format(buffer[0]))

ch-6/2-techniques/shift_bits.py

@@ -0,0 +1,49 @@
+"""Shifting a register.
+Default shift direction is in from the left.
+Space is made for the new value, and n bits from the source are 
+shifted in.
+"""
+import rp2pio
+import adafruit_pioasm
+import array
+
+
+program = f"""
+.program debug_register    
+    set y, {0b10011}       ; set a value in y
+
+; send it to be printed
+    mov isr, y
+    push noblock    ; and use PUSH to put it on the receive FIFO
+
+; shift pts
+    in null, 32     ; clear the isr
+    in y,3         ; get n bits from y
+
+    ; now send it to be printed
+    push noblock    ; and use PUSH to put it on the receive FIFO
+
+; show state of y
+    mov isr, y
+    push noblock
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+## set up a statemachine
+sm = rp2pio.StateMachine(
+    assembled,
+    frequency=2000,
+)
+
+buffer = array.array('I', [0])
+
+# read the data
+sm.readinto(buffer)
+print("Before shift: {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+
+sm.readinto(buffer)
+print("ISR shifted:  {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))
+
+sm.readinto(buffer)
+print("Y state:      {0} 0b{0:032b} 0x{0:x}".format(buffer[0]))

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

@@ -3,13 +3,14 @@ Then turn the wheel slowly to see the change"""
 import board
 import rp2pio
 import adafruit_pioasm
+import array
 
-pio_input = """
+program = """
 .program pio_input    
     set y, 0            ; clear y
 read:
     mov x, y            ; store old Y in x
-    in null, 31         ; Clear ISR
+    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
@@ -20,22 +21,18 @@ different:
     jmp read            ; loop back
 """
 
-assembled = adafruit_pioasm.assemble(pio_input)
+assembled = adafruit_pioasm.assemble(program)
 
 ## set up a statemachine
 sm = rp2pio.StateMachine(
     assembled,
-    frequency=2000,
+    frequency=20000,
     first_in_pin=board.GP20,
     in_pin_count=2
 )
 
-buffer = bytearray(1) # an array of bytes to read into - we are just asking for a byte (are we though? It might be 4 bytes)
+buffer = array.array('I', [0])
 
 while True:
-    # read data from the fifo
-    # print (sm.in_waiting)
-    if sm.in_waiting:
-        data = sm.readinto(buffer)
-        # print it.
-        print("{:08b}".format(buffer[0]))
+    sm.readinto(buffer)
+    print("{:032b}".format(buffer[0]))

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

@@ -3,8 +3,9 @@ Then turn the wheel slowly to see the change"""
 import board
 import rp2pio
 import adafruit_pioasm
+import array
 
-pio_input = """
+program = """
 .program pio_input    
     set y, 0            ; clear y
 read:
@@ -20,7 +21,7 @@ different:
     jmp read            ; loop back
 """
 
-assembled = adafruit_pioasm.assemble(pio_input)
+assembled = adafruit_pioasm.assemble(program)
 
 ## set up a statemachine
 left_enc = rp2pio.StateMachine(
@@ -37,7 +38,7 @@ right_enc = rp2pio.StateMachine(
     in_pin_count=2
 ) 
 
-buffer = bytearray(1) # an array of bytes to read into - we are just asking for a byte (are we though? It might be 4 bytes)
+buffer = array.array('I', [0])
 
 left_data = 0
 right_data = 0

ch-6/4-quadrature-encoding/pio_encoder_counting.py

@@ -0,0 +1,93 @@
+"""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 = """
+; use the osr for count
+; input pins c1 c2
+
+    set y, 0            ; clear y
+    mov osr, y          ; and clear osr
+read:
+    ; x will be the old value
+    ; y the new values
+    mov x, y            ; store old Y in x
+    in null, 32         ; Clear ISR - using y
+    in pins, 2          ; read two pins into y
+    mov y, isr
+    jmp x!=y, different ; Jump if its different
+    jmp read            ; otherwise loop back to read
+
+different:
+    ; x has old value, y has new.
+    ; extract the upper bit of X.
+    in x, 31             ; get bit 31 - old p1 (remember which direction it came in)
+    in null, 31         ; keep only 1 bit
+    mov x, isr          ; put this back in x
+    jmp !x, c1_old_zero
+
+c1_old_not_zero:
+    jmp pin, count_up
+    jmp count_down
+
+c1_old_zero:
+    jmp pin, count_down
+    ; fall through
+count_up:
+    ; for a clockwise move - we'll add 1 by inverting
+    mov x, ~ osr        ; store inverted OSR on x
+    jmp x--, fake       ; use jump to take off 1
+fake:
+    mov x, ~ x          ; invert back
+    jmp send
+count_down:
+    ; for a clockwise move, just take one off
+    mov x, osr          ; store osr in x
+    jmp x--, send       ; dec and send
+send:
+    ; send x.
+    mov isr, x          ; send it
+    push noblock        ; put ISR into input FIFO
+    mov osr, x          ; put X back in OSR
+    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,
+    jmp_pin=board.GP21,
+    in_pin_count=2
+)
+
+right_enc = rp2pio.StateMachine(
+    assembled,
+    frequency=0,
+    first_in_pin=board.GP26,
+    jmp_pin=board.GP27,
+    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(left_data, right_data)
+    if right_enc.in_waiting:
+        right_enc.readinto(buffer)
+        right_data = buffer[0]
+        # print it.
+        print(left_data, right_data)

ch-6/7-demos/encoder_mouse_demo.py

@@ -0,0 +1,24 @@
+"""Copy the adafruit_hid folder into CIRCUITPY, run this,
+and move the wheels on the robot. Why? Why not."""
+import robot
+import usb_hid
+from adafruit_hid.mouse import Mouse
+
+print("Setting up Hid")
+mouse = Mouse(usb_hid.devices)
+
+last_x = 0
+last_y = 0
+
+print("Entering main loop")
+while True:
+  x = robot.left_encoder.read()
+  y = robot.right_encoder.read()
+
+  x_diff = x - last_x
+  y_diff = y - last_y
+
+  last_x = x
+  last_y = y
+
+  mouse.move(x=x_diff, y=y_diff)

ch-6/7-demos/measure_fixed_time.py

@@ -0,0 +1,9 @@
+import time
+import robot
+
+robot.set_left(0.8)
+robot.set_right(0.8)
+
+time.sleep(1)
+robot.stop()
+print(robot.left_encoder.read(), robot.right_encoder.read())

ch-6/7-demos/pio_encoder.py

@@ -0,0 +1,77 @@
+import rp2pio
+import adafruit_pioasm
+import array
+
+program = """
+; use the osr for count
+; input pins c1 c2
+
+    set y, 0            ; clear y
+    mov osr, y          ; and clear osr
+read:
+    ; x will be the old value
+    ; y the new values
+    mov x, y            ; store old Y in x
+    in null, 32         ; Clear ISR - using y
+    in pins, 2          ; read two pins into y
+    mov y, isr
+    jmp x!=y, different ; Jump if its different
+    jmp read            ; otherwise loop back to read
+
+different:
+    ; x has old value, y has new.
+    ; extract the upper bit of X.
+    in x, 31             ; get bit 31 - old p1 (remember which direction it came in)
+    in null, 31         ; keep only 1 bit
+    mov x, isr          ; put this back in x
+    jmp !x, c1_old_zero
+
+c1_old_not_zero:
+    jmp pin, count_up
+    jmp count_down
+
+c1_old_zero:
+    jmp pin, count_down
+    ; fall through
+count_up:
+    ; for a clockwise move - we'll add 1 by inverting
+    mov x, ~ osr        ; store inverted OSR on x
+    jmp x--, fake       ; use jump to take off 1
+fake:
+    mov x, ~ x          ; invert back
+    jmp send
+count_down:
+    ; for a clockwise move, just take one off
+    mov x, osr          ; store osr in x
+    jmp x--, send       ; dec and send
+send:
+    ; send x.
+    mov isr, x          ; send it
+    push noblock        ; put ISR into input FIFO
+    mov osr, x          ; put X back in OSR
+    jmp read            ; loop back
+"""
+
+assembled = adafruit_pioasm.assemble(program)
+
+class QuadratureEncoder:
+  def __init__(self, first_pin, second_pin, reversed=False):
+    """Encoder with 2 pins. Must use sequential pins on the board"""
+    self.sm = rp2pio.StateMachine(
+        assembled,
+        frequency=0,
+        first_in_pin=first_pin,
+        jmp_pin=second_pin,
+        in_pin_count=2
+    )
+    self.reversed = reversed
+    self._buffer = array.array('i', [0])
+
+  def read(self):
+    while self.sm.in_waiting:
+      self.sm.readinto(self._buffer)
+    if self.reversed:
+      return -self._buffer[0]
+    else:
+      return self._buffer[0]
+ 

ch-6/7-demos/robot.py

@@ -1,5 +1,6 @@
 import board
 import pwmio
+import pio_encoder
 
 motor_A1 = pwmio.PWMOut(board.GP17)
 motor_A2 = pwmio.PWMOut(board.GP16)
@@ -9,6 +10,9 @@ motor_B2 = pwmio.PWMOut(board.GP19)
 right_motor = motor_A1, motor_A2
 left_motor = motor_B1, motor_B2
 
+right_encoder = pio_encoder.QuadratureEncoder(board.GP20, board.GP21, reversed=True)
+left_encoder = pio_encoder.QuadratureEncoder(board.GP26, board.GP27)
+
 def stop():
     motor_A1.duty_cycle = 0
     motor_A2.duty_cycle = 0

ch-6/8-exercises/drive_fixed_count.py

@@ -0,0 +1,13 @@
+import time
+import robot
+
+robot.set_left(0.8)
+robot.set_right(0.8)
+target = 4000
+
+while robot.left_encoder.read() < target or robot.right_encoder.read() < target:
+  if robot.left_encoder.read() >= target:
+    robot.set_left(0)
+  if robot.right_encoder.read() >= target:
+    robot.set_right(0)
+  print(robot.left_encoder.read(), robot.right_encoder.read())

ch-6/simple_pin_test.py

@@ -1,12 +0,0 @@
-import time
-import board
-import digitalio
-
-pin = digitalio.DigitalInOut(board.GP4)
-pin.direction = digitalio.Direction.OUTPUT
-
-while True:
-    pin.value = True
-    time.sleep(0.01)
-    pin.value = False
-    time.sleep(0.01)