From 532ca8915f2ceed0d5eac5212c111d088ec32a01 Mon Sep 17 00:00:00 2001
From: Sofia <sofia@teascade.net>
Date: Fri, 29 May 2026 17:02:24 +0300
Subject: [PATCH] Start adding 16-pin Sparkfun GPIO expander

---
 src/main.rs | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/main.rs b/src/main.rs
index 98f6a53..5e15a61 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -15,6 +15,7 @@ use esp_hal::{
     clock::CpuClock,
     delay::Delay,
     gpio::{Level, Output, OutputConfig},
+    i2c::{self, master::I2c},
     interrupt::software::SoftwareInterruptControl,
     main,
     spi::master::{Config, Spi},
@@ -126,6 +127,34 @@ fn main() -> ! {
     .with_rx(peripherals.GPIO7)
     .with_tx(peripherals.GPIO8);
 
+    let mut i2c = I2c::new(
+        peripherals.I2C0,
+        i2c::master::Config::default().with_frequency(Rate::from_khz(400)),
+    )
+    .unwrap()
+    .with_scl(peripherals.GPIO20)
+    .with_sda(peripherals.GPIO22);
+
+    let mut i2c_rst = Output::new(peripherals.GPIO15, Level::High, OutputConfig::default());
+
+    let test_delay = Delay::new();
+
+    i2c_rst.set_low();
+    test_delay.delay_millis(1000);
+    i2c_rst.set_high();
+
+    log::info!("I2C reset");
+
+    let REG_INTERRUPT_MASK_A = 0x13;
+    let default_address = 0x3e;
+
+    let write_buf = [REG_INTERRUPT_MASK_A];
+    let mut read_buf = [0, 0];
+    i2c.write_read(default_address, &write_buf, &mut read_buf)
+        .unwrap();
+
+    log::info!("Read: {:?}", read_buf);
+
     let mut at_commands = ATCommands::new(sim_rst, sim_pwr_key, uart);
 
     let font_renderer = FontRenderer::create(30);