isppac-powr1014 Lattice Semiconductor Corp., isppac-powr1014 Datasheet - Page 19

• Manufacturer Part Number: isppac-powr1014
• Description: In-system Programmable Power Supply Supervisor, Reset Generator And Sequencing Controller
• Manufacturer: Lattice Semiconductor Corp.

Lattice Semiconductor
VMON Voltage Measurement with the On-chip Analog to Digital Converter (ADC, ispPAC-
POWR1014A Only)
The ispPAC-POWR1014A has an on-chip analog to digital converter that can be used for measuring the voltages at
the VMON inputs.
Figure 2-9. ADC Monitoring VMON1 to VMON10
Figure 2-9 shows the ADC circuit arrangement within the ispPAC-POWR1014A device. The ADC can measure all
analog input voltages through the multiplexer, ADC MUX. The programmable attenuator between the ADC mux and
the ADC can be configured as divided-by-3 or divided-by-1 (no attenuation). The divided-by-3 setting is used to
measure voltages from 0V to 6V range and divided-by-1 setting is used to measure the voltages from 0V to 2V
range.
A microcontroller can place a request for any VMON voltage measurement at any time through the I
PAC-POWR1014A only). Upon the receipt of an I
VMON through the ADC MUX. The ADC output is then latched into the I
Calculation
The algorithm to convert the ADC code to the corresponding voltage takes into consideration the attenuation bit
value. In other words, if the attenuation bit is set, then the 10-bit ADC result is automatically multiplied by 3 to cal-
culate the actual voltage at that VMON input. Thus, the I
ing formula can always be used to calculate the actual voltage from the ADC code.
Voltage at the VMONx Pins
1
Note: ADC_VALUE_HIGH (8 bits), ADC_VALUE_LOW (4 bits) read from I
VMON = I
VMON10
VCCINP
VMON1
VMON2
VMON3
VDDA
2
C Readout Register (12 bits
From I
(ispPAC-POWR1014A Only)
ADC
MUX
4
2
C ADC MUX Register
Programmable Analog
5
Attenuator
÷3 / ÷1
1
1
, converted to decimal) * 2mV
2
C command, the ADC will be connected to the I
VREF- 2.048V
2-19
2
ADC
Internal
C readout register is 12 bits instead of 10 bits. The follow-
2
C/SMBUS interface (ispPAC-POWR1014A only).
10
Digital Multiplier
Programmable
ispPAC-POWR1014/A Data Sheet
x3 / x1
2
C readout registers.
12
(ispPAC-POWR1014A Only)
To I
2
C Readout Register
2
2
C bus (isp-
C selected