drivers: Add NRF24L01 driver (written in pure Python).

Comes with test script.  Copy both files to pyboard and run
"import nrf24l01test".

1 files changed, 100 insertions, 0 deletions

diff --git a/drivers/nrf24l01/nrf24l01test.py b/drivers/nrf24l01/nrf24l01test.py
new file mode 100644
index 000000000..264bc21c8
--- /dev/null
+++ b/drivers/nrf24l01/nrf24l01test.py
@@ -0,0 +1,100 @@
+"""Test for nrf24l01 module."""
+
+import struct
+import pyb
+from pyb import Pin, SPI
+from nrf24l01 import NRF24L01
+
+pipes = (b'\xf0\xf0\xf0\xf0\xe1', b'\xf0\xf0\xf0\xf0\xd2')
+
+def master():
+    nrf = NRF24L01(SPI(2), Pin('Y5'), Pin('Y4'), payload_size=8)
+
+    nrf.open_tx_pipe(pipes[0])
+    nrf.open_rx_pipe(1, pipes[1])
+    nrf.start_listening()
+
+    num_needed = 16
+    num_successes = 0
+    num_failures = 0
+    led_state = 0
+
+    print('NRF24L01 master mode, sending %d packets...' % num_needed)
+
+    while num_successes < num_needed and num_failures < num_needed:
+        # stop listening and send packet
+        nrf.stop_listening()
+        millis = pyb.millis()
+        led_state = max(1, (led_state << 1) & 0x0f)
+        print('sending:', millis, led_state)
+        try:
+            nrf.send(struct.pack('ii', millis, led_state))
+        except OSError:
+            pass
+
+        # start listening again
+        nrf.start_listening()
+
+        # wait for response, with 250ms timeout
+        start_time = pyb.millis()
+        timeout = False
+        while not nrf.any() and not timeout:
+            if pyb.elapsed_millis(start_time) > 250:
+                timeout = True
+
+        if timeout:
+            print('failed, respones timed out')
+            num_failures += 1
+
+        else:
+            # recv packet
+            got_millis, = struct.unpack('i', nrf.recv())
+
+            # print response and round-trip delay
+            print('got response:', got_millis, '(delay', pyb.millis() - got_millis, 'ms)')
+            num_successes += 1
+
+        # delay then loop
+        pyb.delay(250)
+
+    print('master finished sending; succeses=%d, failures=%d' % (num_successes, num_failures))
+
+def slave():
+    nrf = NRF24L01(SPI(2), Pin('Y5'), Pin('Y4'), payload_size=8)
+
+    nrf.open_tx_pipe(pipes[1])
+    nrf.open_rx_pipe(1, pipes[0])
+    nrf.start_listening()
+
+    print('NRF24L01 slave mode, waiting for packets... (ctrl-C to stop)')
+
+    while True:
+        pyb.wfi()
+        if nrf.any():
+            while nrf.any():
+                buf = nrf.recv()
+                millis, led_state = struct.unpack('ii', buf)
+                print('received:', millis, led_state)
+                for i in range(4):
+                    if led_state & (1 << i):
+                        pyb.LED(i + 1).on()
+                    else:
+                        pyb.LED(i + 1).off()
+                pyb.delay(15)
+
+            nrf.stop_listening()
+            try:
+                nrf.send(struct.pack('i', millis))
+            except OSError:
+                pass
+            print('sent response')
+            nrf.start_listening()
+
+print('NRF24L01 test module loaded')
+print('NRF24L01 pinout for test:')
+print('    CE on Y4')
+print('    CSN on Y5')
+print('    SCK on Y6')
+print('    MISO on Y7')
+print('    MOSI on Y8')
+print('run nrf24l01test.slave() on slave, then nrf24l01test.master() on master')