AP33772S USB PD Sink Toolkit

CLI demo and reusable driver for the Diodes Inc. AP33772S USB Power Delivery 3.1 sink controller. The driver talks to the chip over I²C, parses source capabilities, issues power requests (fixed, PPS, AVS), and exposes helpers to monitor protection thresholds and live telemetry.

Features

• Delegated bus abstraction (attach any I²C backend)
• PDO refresh, parsing, and rich introspection helpers
• Request fixed, PPS, AVS, or maximum-power profiles
• Raw register read/write utilities for scripting and debug
• Interactive CLI with history, status view, and command helpers

Building

This toolkit can be built for various targets. For example, it has been tested on a Raspberry Pi setup. Requirements:

• GNU make
• C11 compiler (tested with gcc)
• Linux headers with linux/i2c-dev.h

Compile the toolkit:

make

Generated artifacts:

• ap33772s_demo – interactive CLI/repl
• ap33772s.o – driver object (link into other applications)

Clean the build:

make clean

Running the CLI

The default I²C device is /dev/i2c-4. Override with --device:

./ap33772s_demo --device /dev/i2c-1

Enter interactive mode without extra arguments. Helpful commands:

Command	Description
status	Refresh STATUS, PDO list, voltage/current/temperature measurements
set fixed <idx> <mA>	Request fixed PDO with target current
set pps <idx> <mV> <mA>	Request PPS profile
set avs <idx> <mV> <mA>	Request AVS profile
set max <idx>	Request maximum power for PDO
readreg <reg> <len>	Raw register dump (uses driver delegate)
`dbg on	off`
monitor [ms]	Continuous status polling (default 500 ms)

Type help in the shell for the full command list.

Embedding the Driver

Link against ap33772s.c and provide an ap33772s_bus_delegate implementation:

int my_bus_read(void *ctx, uint8_t reg, uint8_t *data, size_t len);
int my_bus_write(void *ctx, uint8_t reg, const uint8_t *data, size_t len);
void my_delay_us(void *ctx, unsigned int usec);

struct ap33772s_bus_delegate delegate = {
    .read = my_bus_read,
    .write = my_bus_write,
    .delay_us = my_delay_us,
    .ctx = my_context_pointer,
};

ap33772s_ref dev = ap33772s_init(&delegate);

The delay_us delegate should block for at least the requested duration; the driver uses it between NTC calibration writes and while waiting for PDO updates during reset.

After initialisation you can refresh capabilities, request PDOs, and query telemetry:

ap33772s_get_power_capabilities(dev);
ap33772s_request_fixed_pdo(dev, 2, 3000);  // 9 V @ 3 A (Depends on device caps)
int voltage_mv;
ap33772s_read_vreq(dev, &voltage_mv);

When finished call

ap33772s_destroy(dev);

License

This project is released under the Apache License 2.0. SPDX identifiers in the sources point to the full terms; include the required NOTICE and license text when redistributing.

Board Notes

• Ensure the AP33772S is powered and connected to the chosen /dev/i2c-* bus.
• The CLI toggles debug prints through the driver delegate; default is enabled.
• Overcurrent/temperature/voltage protections ship enabled via datasheet defaults.