---
author: Silvano Cortesi
date: 18.11.2024
title: AEM10900 Driver
---

```{=org}
#+LICENSE: LGPL-3.0
```
This repository contains driver for the AEM10900 energy harvester.

> The AEM10900 is a fully integrated and compact battery charger circuit
> that extracts DC power from a solar cell to store energy in a
> rechargeable battery. This compact and ultra- efficient battery
> charger allows to extend battery lifetime and eliminates the primary
> energy storage in a large range of wireless application, such as
> wearable and medical applications and Smart sensors. Thanks to its
> Maximum Power Point Tracking and its ultra-low power boost converter,
> the AEM10900 harvests the maximum available input power from a source
> to charge a storage element, such as a Li-ion battery. The boost
> converter operates with input voltages in a range from 115 mV to 1.5
> V. With its unique cold-start circuit, it can start operating with an
> input voltage as low as 250 mV and an input power of only 5 μW. The
> output voltages are in a range of 2.8 V to 4.8 V. --
> [e-peas](https://e-peas.com/product/aem10900-solar-battery-charger/)

The repository is build on top of the datasheet
[DS-AEM10900-v1.5](https://e-peas.com/wp-content/uploads/datasheets/ds-aem10900-v1-5.pdf)
and contains:

## The [YAML](aem10900.yaml) specification of the driver, as used by Reginald to create the struct fields

### YAML Transpile Instruction

The yaml file can be automatically parsed using
[Reginald](https://github.com/schilkp/reginald), based on branch
`schilkp/rust`, commit `dc4ff0d`.

1.  Rust version

    The rust version is built (from within [rust*src*](rust/src/))
    using:

    ``` {.bash org-language="sh"}
    reginald gen -i ../../aem10900.yaml -o registers.rs rs-structs --enum-derive "Debug" --struct-derive "Debug" --enum-derive "PartialEq" --struct-derive "PartialEq"
    ```

2.  C version

    The C version is built (from within [c/](c/)) using:

    ``` {.bash org-language="sh"}
    reginald gen -i ../aem10900.yaml -o aem10900_reg.h c-funcpack
    ```

3.  Markdown Datasheet

    The [markdown datasheet](aem10900_reg.md) is build (from within
    [/](README.org)) by using:

    ``` {.bash org-language="sh"}
    reginald gen -i ./aem10900.yaml -o aem10900.md md-datasheet
    ```

## Rust driver

The rust driver consists of [lib.rs](rust/src/lib.rs),
[device.rs](rust/src/device.rs), [config.rs](rust/src/config.rs),
[error.rs](rust/src/error.rs) and [registers.rs](rust/src/registers.rs).
`registers.rs` is the only auto-created file using reginald, and
contains the register structs as well as pack/unpack functions.

## C driver

The C driver consists of [aem10900.c](c/aem10900.c),
[aem10900.h](c/aem10900.h) and [aem10900~reg~.h](c/aem10900_reg.h).
`aem10900_reg.h` is the only auto-created file using reginald, and
contains the register structs as well as pack/unpack functions.

## Example projects for C and Rust

The example projects make automatically use of the drivers described
above, and can be used as a reference for the implementation. The
following pinout holds:

  Peripheral    Functionality
  ------------- ---------------------------------------
  I2C1          I2C peripheral used for communication
  PB8           SCL pin used together with I2C1
  PB7           SDA pin used together with I2C1
  GPDMA1~CH0~   DMA channel for TX on I2C1
  GPDMA1~CH1~   DMA channel for RX on I2C1