aduc7030 Analog Devices, Inc., aduc7030 Datasheet - Page 66

• Manufacturer Part Number: aduc7030
• Description: Integrated Precision Battery Sensor For Automotive
• Manufacturer: Analog Devices, Inc.

ADuC7030/ADuC7033
Low Power Voltage Reference Scaling Factor
Name:
Address:
Default Value:
Access:
Function:
If the LPM Voltage Reference is 1% below 1.200V, then the value of ADCREF will be approximately 0x7EB9
If the LPM Voltage Reference is 1% above 1.200V, then the value of ADCREF will be approximately 0x8147
This register corrects the effective value of the LPM reference at the temperature the reference is measured at during ADI's production
flow, which is 25°C. There is no change to the Temperature-Coefficient of the LPM reference when using the ADCREF MMR..
This register should not be used if the Precision Reference is being used in Low power mode (if ADCMDE[5] is set.)
ADC POWER MODES OF OPERATION
The ADCs can be configured into various reduced or full
‘power’ modes of operation by configuring ADCMDE[4:3] as
appropriate. The ARM7 MCU can itself also be configured in
Low Power modes of operation (POWCON[5:3]). The core
power modes are independently controlled and are not related
to the ADC power modes described here. The ADC power
modes of operation are described in more detail below.
ADC Startup Procedure
Prior to beginning converting, the following procedure should
be followed.
1.
2.
3.
4.
5.
ADC Normal Power Mode
In Normal Mode, the Current and Voltage/Temperature
channels are fully enabled. The ADC modulator clock is
512KHz and enables the ADCs to provide regular conversion
results at a rate of between 4Hz and 8KHz (see ADCFLT). Both
channels are under full control of the MCU and can be
reconfigured at any time. The default ADC update rate for all
channels in this mode is 1.0kHz
Configure the Current ADC, ADC0, into Low-Power-
Mode (ADC0CON = 0x8007; ADCMDE = 0x09)
Delay for 200µs.
Switch the Current ADC, ADC0, into Idle-Mode
(ADCMDE = 0x03), keeping ADC0CON unchanged. If the
Voltage or Temperature channels are to be used, they
should be enabled here.
Delay for 1ms
Switch ADCMDE to desired mode, for example.
ADCMDE = 0x1.
ADCREF
0xFFFF057C
Part Specific, factory programmed
Read/Write. Care should be taken not to write to this register.
This allows user code to correct for the initial error of the LPM reference. 0x8000 corresponds to no error when
compared to the Normal Mode Reference. The magnitude of the ADC result should be multiplied by the value in
ADCREF and divided by 0x8000 to compensate for the actual value of the low power reference
Rev. PrE | Page 66 of 150
It is worth emphasizing that I-ADC and V/T-ADC channels can
be configured to initiate periodic, normal power mode, high
accuracy, single conversion cycles before returning to ADC full
power-down mode. This flexibility is facilitated under full MCU
control via the ADCMDE MMR and ensures that continuous
periodic monitoring of battery current, voltage and temperature
settings is feasible while ensuring the average dc current
consumption is minimized.
In ADC Normal Mode, the PLL must not be powered down.
ADC Low Power Mode
In ADC Low Power mode, the I-ADC is enabled in a reduced
power and reduced accuracy configuration. The ADC
modulator clock is now driven directly from the on-chip
131kHz low power oscillator, which allows the ADC to be
configured at update rates as low as 1Hz (ADCFLT). The gain
of the ADC in this mode is fixed at 128.
All of the ADC peripheral functions (result counter, digital
comparator and accumulator) described earlier in normal
power mode can still be enabled in low power mode.
Typically, in Low Power Mode, the I-ADC only, is configured to
run at a low update rate, continuously monitoring battery
current. The MCU will be in power-down mode and will only
be woken up when the I-ADC interrupts the MCU. This would
happen after the I-ADC detects a current conversion beyond a
pre-programmed threshold, set-point or a set number of
conversions.
It is also possible to select either the ADC Precision Voltage
Reference or the ADC Low Power Mode Voltage Reference via
ADCMDE[5].
Preliminary Technical Data