nrf5/examples: Updating mountsd example with comment from deleted sdcard.py on how to wire SD directly to SPI.

nrf5/examples/mountsd.py

@@ -1,8 +1,35 @@
+"""
+
+Example for pca10040 / nrf52832 to show how mount
+and list a sdcard connected over SPI.
+
+
+Direct wireing on SD card (SPI):
+   ______________________________
+  |                              \
+  |             9.    | NC    |   \
+  |             1.      | ~CS   | |
+  |             2.      | MOSI  | |
+  |             3.      | GND   | |
+  |             4.      | VCC3.3| |
+  |             5.      | SCK   | |
+  |             6.      | GND   | |
+  |             7.      | MISO  | |
+  |             8.      | NC    | |
+  |                               |
+  ---------------------------------
+"""
+
 import os
 from machine import SPI, Pin
 from sdcard import SDCard
 
-def mount_sd():
-    sd = SDCard(SPI(0), Pin("A22", mode=Pin.OUT))
+def mnt():
+    cs = Pin("A22", mode=Pin.OUT)
+    sd = SDCard(SPI(0), cs)
     os.mount(sd, '/')
 
+def list():
+    files = os.listdir()
+    print(files)
+