From 031d3888e837fa2ef23e92e3923ddc10defbcbf8 Mon Sep 17 00:00:00 2001
From: mz-fuzzy <mzfuzzy800@gmail.com>
Date: Mon, 25 Jan 2016 00:30:05 +0000
Subject: [PATCH] Added possibility/demonstration of IRQ pin usage for
 RPi/Python. Clean-up/fix of RF24 configuration examples in RPi/Python
 example.

Signed-off-by: mz-fuzzy <mzfuzzy800@gmail.com>
---
 examples_RPi/pingpair_dyn.py | 60 +++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 24 deletions(-)

diff --git a/examples_RPi/pingpair_dyn.py b/examples_RPi/pingpair_dyn.py
index 0459ef4cb..76ea5141d 100755
--- a/examples_RPi/pingpair_dyn.py
+++ b/examples_RPi/pingpair_dyn.py
@@ -9,18 +9,17 @@
 from __future__ import print_function
 import time
 from RF24 import *
+import RPi.GPIO as GPIO
 
+irq_gpio_pin = None
 
 ########### USER CONFIGURATION ###########
 # See https://github.com/TMRh20/RF24/blob/master/RPi/pyRF24/readme.md
 
 # CE Pin, CSN Pin, SPI Speed
 
-# Setup for GPIO 22 CE and GPIO 25 CSN with SPI Speed @ 1Mhz
-#radio = RF24(RPI_V2_GPIO_P1_22, RPI_V2_GPIO_P1_18, BCM2835_SPI_SPEED_1MHZ)
-
-# Setup for GPIO 22 CE and CE0 CSN with SPI Speed @ 4Mhz
-#radio = RF24(RPI_V2_GPIO_P1_15, BCM2835_SPI_CS0, BCM2835_SPI_SPEED_4MHZ)
+# Setup for GPIO 22 CE and CE0 CSN with SPI Speed @ 8Mhz
+#radio = RF24(RPI_V2_GPIO_P1_15, BCM2835_SPI_CS0, BCM2835_SPI_SPEED_8MHZ)
 
 #RPi B
 # Setup for GPIO 15 CE and CE1 CSN with SPI Speed @ 8Mhz
@@ -28,9 +27,27 @@
 
 #RPi B+
 # Setup for GPIO 22 CE and CE0 CSN for RPi B+ with SPI Speed @ 8Mhz
-radio = RF24(RPI_BPLUS_GPIO_J8_22, RPI_BPLUS_GPIO_J8_24, BCM2835_SPI_SPEED_8MHZ)
+radio = RF24(RPI_BPLUS_GPIO_J8_15, RPI_BPLUS_GPIO_J8_24, BCM2835_SPI_SPEED_8MHZ)
+
+# Setup for connected IRQ pin, GPIO 24 on RPi B+; uncomment to activate
+#irq_gpio_pin = RPI_BPLUS_GPIO_J8_18
 
 ##########################################
+def try_read_data(channel=0):
+    if radio.available():
+        while radio.available():
+            len = radio.getDynamicPayloadSize()
+            receive_payload = radio.read(len)
+            print('Got payload size={} value="{}"'.format(len, receive_payload.decode('utf-8')))
+            # First, stop listening so we can talk
+            radio.stopListening()
+
+            # Send the final one back.
+            radio.write(receive_payload)
+            print('Sent response.')
+
+            # Now, resume listening so we catch the next packets.
+            radio.startListening()
 
 pipes = [0xF0F0F0F0E1, 0xF0F0F0F0D2]
 min_payload_size = 4
@@ -53,6 +70,12 @@
 
 if inp_role == '0':
     print('Role: Pong Back, awaiting transmission')
+    if irq_gpio_pin is not None:
+        # set up callback for irq pin
+        GPIO.setmode(GPIO.BCM)
+        GPIO.setup(irq_gpio_pin, GPIO.IN, pull_up_down=GPIO.PUD_UP)
+        GPIO.add_event_detect(irq_gpio_pin, GPIO.FALLING, callback=try_read_data)
+
     radio.openWritingPipe(pipes[1])
     radio.openReadingPipe(1,pipes[0])
     radio.startListening()
@@ -103,22 +126,11 @@
         # Pong back role.  Receive each packet, dump it out, and send it back
 
         # if there is data ready
-        if radio.available():
-            while radio.available():
-                # Fetch the payload, and see if this was the last one.
-	            len = radio.getDynamicPayloadSize()
-	            receive_payload = radio.read(len)
-
-	            # Spew it
-	            print('Got payload size={} value="{}"'.format(len, receive_payload.decode('utf-8')))
-
-            # First, stop listening so we can talk
-            radio.stopListening()
-
-            # Send the final one back.
-            radio.write(receive_payload)
-            print('Sent response.')
-
-            # Now, resume listening so we catch the next packets.
-            radio.startListening()
+        if irq_gpio_pin is None:
+            # no irq pin is set up -> poll it
+            try_read_data()
+        else:
+            # callback routine set for irq pin takes care for reading -
+            # do nothing, just sleeps in order not to burn cpu by looping
+            time.sleep(1000)