
Analog Integrated Circuit Device Data
Freescale Semiconductor
92
PC34708
Functional Block Requirements and Behaviors
10 Bit ADC Core Block Description and Application Information
calibration applied. The same applies for when going below the minimum input where the corresponding 0000 DEC reading may
not be returned.
7.6.2.2
Control
The ADC parameters are programmed by the processor via the SPI. When a reading sequence is finished, an interrupt
ADCDONEI is generated. The interrupt can be masked with the ADCDONEM bit.
The ADC is automatically calibrated every time the PMIC is powered on.
The ADC is enabled by setting ADEN bit high. The ADC can start a series of conversions through SPI programming by setting
the ADSTART bit. If the ADEN bit is low, the ADC will be disabled and in low power mode. The ADC is automatically calibrated
every time PMIC is powered.
The conversions will begin after a small analog synchronization of up to 30 microseconds, plus a programmable delay from 0
(default) up to 600
μS, by programming the bits ADDLY1[3:0]. The ADDLY2[3:0] controls the delay between each of the
conversions from 0 to 600
μS. ADDLY3[3:0] controls the delay after the final conversion, and is only valid when ADCONT is high.
ADDLY1, 2, and 3 are set to 0 by default.
There is a max of 8 conversions that will take place when the ADC is started. The register ADSELx[3:0] selects the channel which
the ADC will read and store in the ADRESULTx register. The ADC will always start at the channel indicated in ADSEL0, and read
up to and including the channel set by the ADSTOP[2:0] bits. For example, when ADSTOP[2:0] = 010, it will request the ADC to
read channels indicated in ADSEL0, ADSEL1, and ADSEL2. When ADSTOP[2:0] = 111, all eight channels programmed by the
value in ADSEL0-7 will be read. When the ADCONT bit is set high, it allows the ADC to continuously loop and read the channels
from address 0 to the stop address programmed in ADSTOP. By default, the ADCONT is set low (disabled). In the continuous
mode, the ADHOLD bit will allow the software to hold the ADC sequencer from updating the results register while the ADC results
are read. Once the sequence of A/D conversions is complete, the ADRESULTx results are stored in 4 SPI registers (ADC 4 -
ADC 7).
Table 91. ADDLYx[3:0]
ADDLYx[3:0]
Delay in
μs
0000
0
0001
40
0010
80
0011
120
0100
160
0101
200
0110
240
0111
280
1000
320
1001
360
1010
400
1011
440
1100
480
1101
520
1110
560
1111
600