UPS PIco HV3.0A Firmware Code 040 Print Date 18.08.2017
Designed and Manufactured by PiModules and ModMyPi
www.pimodules.com www.modmypi.com
Raspberry Pi® GPIO 5V Level
External Powering Level
UPS PIco HV3.0 12-bit A/D converters
The UPS PIco HV3.0 is equipped with 3 x 12 bits A/D converters. Access to their
conversion data is possible via dedicated registers placed at the I
2
C address 0x69
(0x14, 0x16, 0x18). Those A/D converters read continuously data every 250 uS with
conversion time of 3.5 uS per sample. However due to implemented low noise
software enhanced filtering in the firmware the effective rate data rate is around of
0.001 sec per reading (each A/D register values is refreshed every 1000us).
Each of the A/D converters is pre-scaled to measure voltage 0-5.2V with implemented
on the UPS PIco HV3.0 HAT resistor divider. They are named aEXT0, aEXT1, aEXT2.
However, there is also a possibility for the user (if use Terminal Block PCB or additional
external resistor) to use two of them as pre scaled of 0-10V, 0-20V, or 0-30V. These
two A/D converters are named aEXT1 and aEXT2.
Due to electrical requirements of the integrated A/D converters the impedance is set
to low values, therefore some high impedance sensors cannot be read properly as
could require higher impedance of A/D converter interface. On such cases it is
recommended to use Voltage Follower that converts the sensor high impedance to
UPS PIco HV3.0 HAT A/D converters lower one.
This functionality (of the Voltage Follower) has been implemented on the Terminal
Blocks PCB, where on one of the A/
D’s converters (the aEXT0) a Voltage Follower has
been assigned and allows to convert high impedance of any possible used sensor to
low impedance on the A/D side. A detailed description of the Terminal Blocks PCB and
their functionalities are described in separate section of this manual.
The basic circuit of all A/D converters (the resistor dividers) are shown here below, it
is same to all implemented A/D converters in the UPS PIco HV3.0 HAT.
