Datasheet

UniPi

EEPROM

UniPi features onboard EEPROM (24C02) for storing important information with 2k bit memory

organized into single block of 256 * 8-bit. We reserve address space 0xe0 – 0xff the rest is left for

user space. The rest of unused reserved bytes are nulled.

Table 4 - memory organization

Starting address

Number of bytes

Example

Description

0xe0

fa-55

UniPi identification

0xe2

1.1

UniPi version

0xf0

0x40b089c5 (5.516818)

AI1 coefficient

0xf4

0x40b08b44 (5.517)

AI2 coefficient

Analog Output

Analog output is driven by the GPIO 18 PWM signal and is designed to run at 400Hz. The GPIO port is

galvanically isolated from the rest of the output. The maximum current driven from this output is

20mA. This output is meant to control 3

party devices that can adjust its power according to the 0-

10V. The precision of AO in UniPi v1.0 is +-5% but also depends of the Raspberry Pi CPU usage.

External voltage must be connected to the AOV connector with maximum voltage of 35V DC.

Make sure to adjust output voltage using the blue trimmer (labeled as R49) before connecting

devices to avoid causing damage.

Behavior of the AO has changed since the UniPi version 1.1 (incl.). Before that 100% duty cycle on

PWM meant to output 0V, and 0% DC (or permanent low) meant 10V. But after the version 1.1

(including v 1.1) the process is different and more logic meaning 100% duty cycle is 10V and 0% is 0V.