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docs/library/pyb.ADC: Remove outdated ADCAll code example.

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Peter Hinch 2018-04-11 09:14:05 +01:00 committed by Damien George
parent d12483d936
commit 0600645944
1 changed files with 3 additions and 40 deletions
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docs/library/pyb.ADC.rst
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@ -170,44 +170,7 @@ The ADCAll Object
The default value is 0xffffffff which means all analog inputs are active. If just the internal
channels (16..18) are required, the mask value should be 0x70000.
It is possible to access channle 16..18 values without incurring the side effects of ``ADCAll``::
def adcread(chan): # 16 temp 17 vbat 18 vref
assert chan >= 16 and chan <= 18, 'Invalid ADC channel'
start = pyb.millis()
timeout = 100
stm.mem32[stm.RCC + stm.RCC_APB2ENR] |= 0x100 # enable ADC1 clock.0x4100
stm.mem32[stm.ADC1 + stm.ADC_CR2] = 1 # Turn on ADC
stm.mem32[stm.ADC1 + stm.ADC_CR1] = 0 # 12 bit
if chan == 17:
stm.mem32[stm.ADC1 + stm.ADC_SMPR1] = 0x200000 # 15 cycles
stm.mem32[stm.ADC + 4] = 1 << 23
elif chan == 18:
stm.mem32[stm.ADC1 + stm.ADC_SMPR1] = 0x1000000
stm.mem32[stm.ADC + 4] = 0xc00000
else:
stm.mem32[stm.ADC1 + stm.ADC_SMPR1] = 0x40000
stm.mem32[stm.ADC + 4] = 1 << 23
stm.mem32[stm.ADC1 + stm.ADC_SQR3] = chan
stm.mem32[stm.ADC1 + stm.ADC_CR2] = 1 | (1 << 30) | (1 << 10) # start conversion
while not stm.mem32[stm.ADC1 + stm.ADC_SR] & 2: # wait for EOC
if pyb.elapsed_millis(start) > timeout:
raise OSError('ADC timout')
data = stm.mem32[stm.ADC1 + stm.ADC_DR] # clear down EOC
stm.mem32[stm.ADC1 + stm.ADC_CR2] = 0 # Turn off ADC
return data
Example::
def v33():
return 4096 * 1.21 / adcread(17)
def vbat():
return 1.21 * 2 * adcread(18) / adcread(17) # 2:1 divider on Vbat channel
def vref():
return 3.3 * adcread(17) / 4096
def temperature():
return 25 + 400 * (3.3 * adcread(16) / 4096 - 0.76)
Note that this example is only valid for the F405 MCU and all values are not corrected by Vref and
factory calibration data.
adcall = pyb.ADCAll(12, 0x70000) # 12 bit resolution, internal channels
temp = adcall.read_core_temp()