lowpower: disable_pins added and defaulted False.

Author: peterhinch

lowpower/README.md

@@ -1,6 +1,6 @@
 # A low power usayncio adaptation
 
-Release 0.12 23rd April 2019
+Release 0.13 17th Oct 2019
 
 API changes: low power applications must now import `rtc_time_cfg` and set its
 `enabled` flag.  
@@ -21,6 +21,7 @@ This module is specific to Pyboards including the D series.
    3.2.3 [Current waveforms Pyboard 1](./README.md#323-current-waveforms-pyboard-1)  
    3.2.4 [Pyboard D measurements](./README.md#324-pyboard-d-measurements)  
  4. [The rtc_time module](./README.md#4-the-rtc_time-module)  
+  4.1 [rtc_time_cfg](./README.md#41-rtc_time_cfg)  
  5. [Application design](./README.md#5-application-design)  
   5.1 [Hardware](./README.md#51-hardware)  
   5.2 [Application Code](./README.md#52-application-code)  
@@ -327,6 +328,22 @@ around or to make it global. Once instantiated, latency may be changed by
 Latency(t)
 ```
 
+## 4.1 rtc_time_cfg
+
+This consists of the following:
+```python
+enabled = False
+disable_3v3 = False
+disable_leds = False
+disable_pins = False
+```
+These variables may selectively be set `True` by the application prior to
+importing `uasyncio`. Setting `enabled` is mandatory if low power mode is to be
+engaged. The other variables control the 3.3V regulator, the LED drivers and
+GPIO pins: the latter may be set to inputs with pulldown resistors to minimise
+current draw. Unfortunately at the time of writing this feature seems to have
+a fatal effect. I am investigating.
+
 ###### [Contents](./README.md#a-low-power-usayncio-adaptation)
 
 # 5. Application design

lowpower/rtc_time.py

@@ -12,7 +12,7 @@
 import sys
 import utime
 from os import uname
-from rtc_time_cfg import enabled, disable_3v3, disable_leds
+from rtc_time_cfg import enabled, disable_3v3, disable_leds, disable_pins
 
 if not enabled:  # uasyncio traps this and uses utime
     raise ImportError('rtc_time is not enabled.')
@@ -72,8 +72,9 @@ def low_power_pins():
             pins_bt = ['D5', 'D10', 'E3', 'E4', 'E5', 'E6', 'G8', 'G13', 'G14', 'G15', 'I4', 'I5', 'I6', 'I10']
             pins_qspi1 = ['B2', 'B6', 'D11', 'D12', 'D13', 'E2']
             pins_qspi2 = ['E7', 'E8', 'E9', 'E10', 'E11', 'E13']
-            for p in pins:
-                pyb.Pin(p, pyb.Pin.IN, pyb.Pin.PULL_DOWN)
+            if disable_pins:
+                for p in pins:
+                    pyb.Pin(p, pyb.Pin.IN, pyb.Pin.PULL_DOWN)
             if disable_3v3:
                 pyb.Pin('EN_3V3', pyb.Pin.IN, None)
             if disable_leds:

lowpower/rtc_time_cfg.py

@@ -2,3 +2,4 @@
 enabled = False
 disable_3v3 = False
 disable_leds = False
+disable_pins = False