Add chip identification at boot time

controller/src/chip.rs

+use embassy_stm32::pac;
+
+pub fn identify() {
+    let dbgmcu = pac::DBGMCU.idcode().read();
+    let (density, rev) = match (dbgmcu.dev_id(), dbgmcu.rev_id()) {
+        (0x412, 0x1000) => ("low-density", "A"),
+        (0x412, _) => ("low-density", "?"),
+        (0x410, 0x0000) => ("medium-density", "A"),
+        (0x410, 0x2000) => ("medium-density", "B"),
+        (0x410, 0x2001) => ("medium-density", "Z"),
+        (0x410, 0x2003) => ("medium-density", "1/2/3/X/Y"),
+        (0x414, 0x1000) => ("high-density", "1/A"),
+        (0x414, 0x1001) => ("high-density", "Z"),
+        (0x414, 0x1003) => ("high-density", "1/2/3/X/Y"),
+        (0x414, _) => ("high-density", "?"),
+        (0x430, 0x1000) => ("XL-density", "1/A"),
+        (0x430, _) => ("XL-density", "?"),
+        (0x418, 0x1000) => ("connectivity", "A"),
+        (0x418, 0x1001) => ("connectivity", "Z"),
+        (0x418, _) => ("connectivity", "?"),
+        (_, _) => ("?", "?"),
+    };
+    let flash_size = unsafe { *(0x1FFF_F7E0 as *const u16) };
+    defmt::info!(
+        "Device type: {}, revision: {} – flash size: {}kB",
+        density,
+        rev,
+        flash_size
+    );
+
+    let pid = 0xe00f_ffe0 as *const [u32; 3];
+    let pid = unsafe { *pid };
+    let used = pid[2] & 8 != 0;
+    let identity_code = ((pid[1] & 0xf0) >> 4) | ((pid[2] & 0x7) << 4);
+    let continuation_code = unsafe { *(0xe00f_ffd0 as *const u32) };
+    defmt::info!(
+        "used = {}, identity_code = {:#04x}, continuation_code = {:#04x}",
+        used,
+        identity_code,
+        continuation_code
+    );
+}

controller/src/main.rs

@@ -15,6 +15,7 @@ use embassy_stm32::{
 use panic_probe as _;
 
 pub mod blinker;
+mod chip;
 mod encoders;
 mod logic;
 mod power;
@@ -87,6 +88,8 @@ async fn main(spawner: Spawner) {
         defmt::Debug2Format(&reset_cause),
     );
 
+    chip::identify();
+
     spawner
         .spawn(blinker::blink(p.PB15, blink_pattern(reset_cause)))
         .unwrap();