From 89a603a8644c22ce303d404b3af8967da1a12f9a Mon Sep 17 00:00:00 2001
From: "Peter D. Gray" <peter@conalgo.com>
Date: Fri, 14 May 2021 11:01:00 -0400
Subject: [PATCH] Remove delay_us

---
 stm32/mk4-bootloader/ae.c    |  2 +-
 stm32/mk4-bootloader/delay.c | 17 -----------------
 stm32/mk4-bootloader/delay.h |  6 +++---
 3 files changed, 4 insertions(+), 21 deletions(-)

diff --git a/stm32/mk4-bootloader/ae.c b/stm32/mk4-bootloader/ae.c
index b262b80d..17d46e3b 100644
--- a/stm32/mk4-bootloader/ae.c
+++ b/stm32/mk4-bootloader/ae.c
@@ -280,7 +280,7 @@ ae_wake(void)
     // send zero (all low), delay 2.5ms
     _send_byte(0x00);
 
-    delay_us(2500);     // measured: ~2.9ms
+    delay_ms(3);     // measured: ~2.9ms
 
     _flush_rx();
 }
diff --git a/stm32/mk4-bootloader/delay.c b/stm32/mk4-bootloader/delay.c
index 0049810a..cb4fe605 100644
--- a/stm32/mk4-bootloader/delay.c
+++ b/stm32/mk4-bootloader/delay.c
@@ -25,21 +25,4 @@ delay_ms(int ms)
     }
 }
 
-// delay_us()
-//
-    void
-delay_us(int us)
-{
-    if(us > 1000) {
-        // big round up
-        delay_ms((us + 500) / 1000);
-
-    } else {
-        // XXX calibrate this
-        for(volatile int i=0; i<(10000*us); i++) {
-            __NOP();
-        }
-    }
-}
-
 // EOF
diff --git a/stm32/mk4-bootloader/delay.h b/stm32/mk4-bootloader/delay.h
index dbe881e8..6468deda 100644
--- a/stm32/mk4-bootloader/delay.h
+++ b/stm32/mk4-bootloader/delay.h
@@ -3,7 +3,7 @@
  */
 #pragma once
 
-// Software delay loops (we have no interrupts)
-
+// Uses SYSTICK in polling mode
 void delay_ms(int ms);
-void delay_us(int us);
+
+// EOF