From fc110f07c3c533d9ec6cd061c4b018f70381852e Mon Sep 17 00:00:00 2001
From: 9names <60134748+9names@users.noreply.github.com>
Date: Mon, 3 Oct 2022 11:43:09 +1100
Subject: [PATCH] Add comments for HAL features

---
 rp2040-hal/Cargo.toml | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/rp2040-hal/Cargo.toml b/rp2040-hal/Cargo.toml
index 7794cb9..2781e7f 100644
--- a/rp2040-hal/Cargo.toml
+++ b/rp2040-hal/Cargo.toml
@@ -44,11 +44,23 @@ pio-proc = "0.2.0"
 dht-sensor = "0.2.1"
 
 [features]
+# Minimal startup / runtime for Cortex-M microcontrollers
 rt = ["rp2040-pac/rt"]
+
+# Memoize(cache) ROM function pointers on first use to improve performance
 rom-func-cache = []
+
+# Disable automatic mapping of language features (like floating point math) to ROM functions
 disable-intrinsics = []
+
+# This enables ROM functions for f64 math that were not present in the earliest RP2040s
 rom-v2-intrinsics = []
-rp2040-e5 = [] # USB errata 5: USB device fails to exit RESET state on busy USB bus.
+
+# This enables a fix for USB errata 5: USB device fails to exit RESET state on busy USB bus.
+# Only required for RP2040 B0 and RP2040 B1, but it also works for RP2040 B2 and above
+rp2040-e5 = []
+
+# critical section that is safe for multicore use
 critical-section-impl = ["critical-section/restore-state-u8"]
 
 [[example]]