In differential mode, the
AdcGainCh0
and
AdcGainCh1
parameters can change the selected gain for the two ADC read-
ings, and the
AdcDiff
scale factors and offsets, both supplied by the customer, are used.
AdcGainCh0
- this parameter sets the preamplifier gain applied when making a differential measurement of ADC1 relative
to ADC0. Setting this parameter to 0x00 sets the gain to 1, 0x01 sets the gain to 2, 0x02 sets the gain to 4 and so on, up
to 0x06 which sets the gain to 64. Note that the preamplifier output voltage saturates at 2.4 V regardless of the gain set-
ting.
AdcGainCh1
- this parameter sets the gain applied when making a differential measurement of ADC2 relative to ADC0.
Setting this parameter to 0x00 sets the gain to 1, 0x01 sets the gain to 2, 0x02 sets the gain to 4 and so on, up to 0x06
which sets the gain to 64. Note that the preamplifier output voltage saturates at 2.4 V regardless of the gain setting.
AdcDiffScaleFactorCh0/1 and AdcDiffOffsetCh0/1
- these parameters are applied to the raw ADC readings in differential
mode. These values are not factory calibrated, but can be calibrated by the user.
FastAdcPrescaler
- this parameter is the system clock divisor used to generate the ADC clock when the system is being
clocked at 16 MHz. Default value is 0x05 (system clock
÷
128). Higher values correspond to slower ADC clock rates. For
example, 0x07 =
÷
512, and 0x00 =
÷
4. Note that larger prescalers will increase the amount of time it takes to collect all
readings. DIV4 is not valid when running at 16 MHz because the maximum ADC clock rate is 2 MHz, so DIV8 is the low-
est allowed.
SlowAdcPrescaler
- System clock divisor used to generate the ADC clock when the system is being clocked at 2 MHz,
when exiting sleep mode. Default value is 0x02 (system clock
÷
16). Higher values correspond to slower ADC clock rates.
For example, 0x07 = DIV512, and 0x00 = DIV4.
MaxQueuedEvents -
this parameter sets the maximum number of Event Reports that can be queued at one time by a
DNT90M.
AdcSkipCount
- this parameter sets the number of measurements to skip (discard) when switching to a new ADC channel.
The skipped measurements allow transients in the ADC sample-and-hold circuit to settle out. This parameter must be set
to at least 0x03 when
AdcDiffMode
is selected. Note that the
IoPreDelay
parameter discussed above provides a delay to allow signals
external
to the DNT90M to settle following a
wake up event, while
AdcSkipCount
skips measurements that may be distorted because the
internal
voltage on the ADC
sample-and-hold has not settled.
7.4.8 Bank 0xFF - Special Functions
Bank
Location
Name
R/W
Size
Range
Default
0xFF
0x00
UcReset
W
1
0..2
N/A
0xFF
0x01
MemorySave
W
1
0xD0..0xD2
N/A
0xFF
0x04
DiagSerialRate
R/W
1
0..11
7 (38400 kbps)
0xFF
0x0C
ForceDiscover
W
3
0..255
0.1 s/count
0xFF
0x0E
DiagPortEn
R/W
1
0..1
0 (disabled)
Table 7.4.8.1
UcReset
- writing a 0 to this parameter initiates a full reset, writing 1 to initiates a reset to the serial bootloader, or writing a
2 to initiates a reset to the OTA bootloader client.
©2012 by Murata Electronics N.A., Inc.
DNT90M Integration Guide (2012/09/17)
Page 47 of 74
www.murata.com
