From 167a7dc6a753b5ba11c8c2ae2a365cec8656c171 Mon Sep 17 00:00:00 2001
From: Dave Hodder <dave.hodder@focusrite.com>
Date: Fri, 12 Feb 2016 18:06:50 +0000
Subject: single-page flash storage

---
 include/app.h      | 36 +++++++++++++++++++++++++++++++++++-
 include/app_defs.h |  7 +++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

(limited to 'include')

diff --git a/include/app.h b/include/app.h
index ed946d5..c26c131 100644
--- a/include/app.h
+++ b/include/app.h
@@ -43,7 +43,7 @@
 
 /******************************************************************************
  Button indexing is as follows - numbers in brackets do not correspond to real
-buttons, but can be harmessly sent in hal_set_led.
+ buttons, but can be harmessly sent in hal_set_led.
  
  (90)91 92 93 94 95 96 97 98 (99)
  .......
@@ -92,6 +92,40 @@ void hal_send_midi(u8 port, u8 status, u8 data1, u8 data2);
  */
 void hal_send_sysex(u8 port, const u8* data, u16 length);
 
+/**
+ * Read some data from flash.
+ *
+ * Flash storage is in a single block, currently corresponding to one page.
+ * The block is always USER_AREA_SIZE bytes long. You can read/write any bytes
+ * within it - you do not need to worry about paging, that's handled by the HAL.
+ *
+ * The block size may increase to span multiple pages in future :)
+ *
+ * @param offset - how far into the USER_AREA_SIZE byte block to start reading
+ * @param data - buffer to receive data (must be at least length bytes long)
+ * @param length - bytes to read
+ *
+ * Attempts to read beyond the end of the block will fail silently.
+ *
+ * Note that your first ever read from a new device will contain 0xFF's until
+ * you overwrite them.
+ */
+void hal_read_flash(u32 offset, u8 *data, u32 length);
+
+/**
+ * Write data to flash
+ *
+ * Do take care to avoid thrashing it, as you can wear it out with excessive
+ * writes. The HAL does not currently do anything clever to mitigate this.
+ *
+ * @param offset - how far into the USER_AREA_SIZE byte block to start writing
+ * @param data - buffer to write (must be at least length bytes long)
+ * @param length - bytes to write
+ *
+ * Attempts to write beyond the end of the block will fail silently
+ */
+void hal_write_flash(u32 offset,const u8 *data, u32 length);
+
 // ____________________________________________________________________________
 //
 // Callbacks from the hardware (implemented in your app.c)
diff --git a/include/app_defs.h b/include/app_defs.h
index 829f8a6..7a3efa1 100644
--- a/include/app_defs.h
+++ b/include/app_defs.h
@@ -99,6 +99,13 @@ typedef unsigned char  u8;
 #define	MIDI_IN_CABLE		0
 #define	MIDI_OUT_CABLE		1
 
+// ____________________________________________________________________________
+//
+// Flash storage
+// ____________________________________________________________________________
+
+#define USER_AREA_SIZE 1024
+
 // ____________________________________________________________________________
 
 #endif
-- 
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