rp2040

commit d4782618cbd2c8cc737cba77a7fec5379b8d6bee
parent 3cb08405293f0153822e7301496fc07d15080b37
Author: Matsuda Kenji <info@mtkn.jp>
Date:   Fri,  8 Mar 2024 08:01:25 +0900

move to sram bank 4

Diffstat:
M
ex3/boot2.s
 | 
16
+++++++++++++++-
M
ex3/memmap.ld
 | 
9
+++++----

2 files changed, 20 insertions(+), 5 deletions(-)
diff --git a/ex3/boot2.s b/ex3/boot2.s
@@ -11,11 +11,21 @@ boot2:
 	blx r2
 	blx r0
 
+	// clear sram contents
+	mov r0, #0
+	ldr r3, sram_base
+	ldr r4, sram_end
+mem_clear_loop:
+	str	r0, [r3, #0]
+	add r3, #4
+	cmp r3, r4
+	blt mem_clear_loop
+
 	// load main program to sram
 	ldr r0, =prog_start
 	ldr r1, =prog_size
 	mov r2, #0
-	ldr r3, sram_base
+	ldr r3, sram4_base
 copy:
 	cmp r1, r2
 	blt end
@@ -39,6 +49,10 @@ rom_base:
 	.word 0x00000000
 sram_base:
 	.word 0x20000000
+sram4_base:
+	.word 0x20040000
+sram_end:
+	.word 0x20042000
 m0plus_vtor:
 	.word 0xe0000000 + 0xed08
 literals:
diff --git a/ex3/memmap.ld b/ex3/memmap.ld
@@ -1,7 +1,8 @@
 MEMORY
 {
 	FLASH(rx) : ORIGIN = 0x10000000, LENGTH = 2m
-	SRAM(rwx) : ORIGIN = 0x20000000, LENGTH = 264k
+	SRAM(rwx) : ORIGIN = 0x20000000, LENGTH = 256k
+	SRAM4(rwx) : ORIGIN = 0x20040000, LENGTH = 4k
 }
 
 SECTIONS
@@ -13,13 +14,13 @@ SECTIONS
 	} > FLASH
 	.text : {
 		*(.text)
-	} > SRAM AT > FLASH
+	} > SRAM4 AT > FLASH
 	.data : {
 		*(.data)
-	} > SRAM AT > FLASH
+	} > SRAM4 AT > FLASH
 	.rodata : {
 		*(.rodata)
-	} > SRAM AT > FLASH
+	} > SRAM4 AT > FLASH
 	prog_start = LOADADDR(.text);
 	prog_size = SIZEOF(.text) + SIZEOF(.data) + SIZEOF(.rodata);
 }