Ubah startup.s menjadi ini:
/*********************************************************************
*
* C Runtime Startup
*
*********************************************************************
* Filename: crt0.S
*
* Processor: PIC32
*
* Compiler: MPLAB XC32
* MPLAB X IDE
* Company: Microchip Technology Inc.
*
* Software License Agreement
*
* Copyright (c) 2014, Microchip Technology Inc. and its subsidiaries ("Microchip")
* All rights reserved.
*
* This software is developed by Microchip Technology Inc. and its
* subsidiaries ("Microchip").
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Microchip's name may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY MICROCHIP "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* MICROCHIP BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING BUT NOT LIMITED TO
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWSOEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
********************************************************************/
/* Edited: J. Bajic 2021, v2.15r01 */
/* !!! THIS IS MODIFIED crt0.s (XC32 v2.15) STARTUP CODE FOR USE WITH MIKROE BOOTLOADER !!! */
#include "xc.h"
#include <cp0defs.h>
#define USE_MIKROE_BOOTLOADER /* !!! Added this line, define USE_MIKROE_BOOTLOADER */
#ifdef __LIBBUILD__
# Replace the standard debugging information with a simple filename. This
# prevents the library build directory from showing up in MPLAB IDE. It
# also effectively disables source-line debugging.
.file 1 "libpic32/startup/crt0.S"
.loc 1 0
#endif
#if (__XC32_VERSION > 1000) && !defined(CPP_INIT)
#define CPP_INIT
#endif
#if !defined(PIC32_SRS_SET_COUNT)
# if defined(__PIC32_SRS_SET_COUNT)
# define PIC32_SRS_SET_COUNT __PIC32_SRS_SET_COUNT
# else
# warning PIC32_SRS_SET_COUNT not defined on build line
# define PIC32_SRS_SET_COUNT 2
# endif
#endif
/* !!! Commented this section */
/* !!! Processor header conatains info if PIC32 has init data -> __PIC32_HAS_INIT_DATA */
/*#if defined(__PIC32MX) || defined(__PIC32MM) || defined(__PIC32MZ)*/
/*#define INIT_DATA 1*/
/*#endif*/
/* !!! end of commented section */
/* This file contains 32-bit assembly code */
.set nomips16
##################################################################
# Entry point of the entire application
##################################################################
.section .reset,code,keep
.align 2
.set noreorder
.ent _reset
############################
# Begin ISA switching code #
############################
#if defined (__mips_micromips)
.set micromips
#endif
#if(!defined(USE_MIKROE_BOOTLOADER))/* !!! Added this line, USE_MIKROE_BOOTLOADER defined in CPUconfig.h */
#if (defined(__PIC32_HAS_MICROMIPS)) && (defined(__PIC32_HAS_MIPS32R2))
_reset:
.word 0x10000003 /* MIPS32: branch forward 0x10 bytes from here */
/* MicroMIPS: ADDI32 $0, $0, 0x0007 (nop) */
/* DO NOT change the relative branch */
.word 0x00000000 /* NOP */
__reset_micromips_isa:
.set micromips
jal _startup
nop
.align 2
/* Device not in proper ISA mode */
.set nomicromips
__reset_switch_isa:
jal _startup
nop
#else
_reset:
jal _startup
nop
#endif /* __PIC32_HAS_MICROMIPS */
/* !!! Added reset section, skip isa switching and jump to startup */
#else
# warning Startup set for MIKROE bootloader
_reset:
la k0, _startup
jr k0 # Jump to startup code
nop
#endif
/* !!! end of added reset section */
/* !!! NO CHANGES IN CODE BELOW !!! */
.align 2
.end _reset
.globl _reset
.size _reset, .-_reset
.section .reset.startup,code,keep
.align 2
.set noreorder
#if defined (__mips_micromips)
.set micromips
#else
.set nomicromips
#endif
############################
# End ISA switching code #
############################
##################################################################
# Startup code
##################################################################
.align 2
.globl _startup
.set noreorder
.ent _startup
_startup:
##################################################################
# If entered because of an NMI, jump to the NMI handler.
##################################################################
mfc0 k0,_CP0_STATUS
ext k0,k0,19,1 # Extract NMI bit
beqz k0,_no_nmi
nop
la k0,_nmi_handler
jr k0
nop
_no_nmi:
##################################################################
# Initialize Stack Pointer
# _stack is initialized by the linker script to point to the
# starting location of the stack in DRM
##################################################################
la sp,_stack
##################################################################
# Initialize Global Pointer
# _gp is initialized by the linker script to point to "middle"
# of the small variables region
##################################################################
la gp,_gp
#if (PIC32_SRS_SET_COUNT == 2)
##################################################################
# Initialize Global Pointer in Shadow Set
# The SRSCtl's PSS field must be set to the shadow set in which
# to initialize the global pointer. Since we have only a
# single shadow set (besides the normal), we will initialize
# SRSCtl<PSS> to SRSCtl<HSS>. We then write the global pointer
# to the previous shadow set to ensure that on interrupt, the
# global pointer has been initialized.
##################################################################
mfc0 t1,_CP0_SRSCTL # Read SRSCtl register
add t3,t1,zero # Save off current SRSCtl
ext t2,t1,26,4 # to obtain HSS field
ins t1,t2,6,4 # Put HSS field
mtc0 t1,_CP0_SRSCTL # into SRSCtl<PSS>
ehb # Clear hazard before using new SRSCTL
wrpgpr gp,gp # Set global pointer in PSS
mtc0 t3,_CP0_SRSCTL # Restore SRSCtl
ehb
#elif (PIC32_SRS_SET_COUNT > 2)
##################################################################
# Initialize Global Pointer in Shadow Set(s)
# The SRSCtl PSS field must be set to the shadow set in which
# to initialize the global pointer. We will initialize
# SRSCtl<PSS> to the number of reg sets and work down to set zero.
# We write the global pointer to the previous shadow set to
# ensure that on interrupt, the global pointer has been
# initialized.
##################################################################
mfc0 t1,_CP0_SRSCTL # Read SRSCtl register
add t3,t1,zero # Save off current SRSCtl
li t2,(PIC32_SRS_SET_COUNT-1)
1: ins t1,t2,6,4 # Put next shadow set field
mtc0 t1,_CP0_SRSCTL # into SRSCtl<PSS>
ehb # Clear hazard before using new SRSCTL
wrpgpr gp,gp # Set global pointer in PSS
addiu t2,t2,-1 # Next lower shadow set
# Loop for all sets
bne t2,$0,1b # Down to zero (normal GPR set)
nop
mtc0 t3,_CP0_SRSCTL # Restore SRSCtl
ehb
#endif /* (PIC32_SRS_SET_COUNT > 2) */
##################################################################
# Call the "on reset" procedure
##################################################################
la t0,_on_reset
jalr t0
nop
#if defined(INIT_MMU_MZ_FIXED) || defined(__PIC32_HAS_MMU_MZ_FIXED)
##################################################################
# Initialize TLB for fixed mapping to EBI and SQI
##################################################################
.extern __pic32_tlb_init_ebi_sqi
la t0,__pic32_tlb_init_ebi_sqi
jalr t0
nop
#endif
##################################################################
# Clear uninitialized data sections
##################################################################
_start_bss_init:
la t0,_bss_begin
la t1,_bss_end
b _bss_check
nop
_bss_init:
sw zero,0x0(t0)
sw zero,0x4(t0)
sw zero,0x8(t0)
sw zero,0xc(t0)
addu t0,16
_bss_check:
bltu t0,t1,_bss_init
nop
#if defined(INIT_L1_CACHE) || defined(__PIC32_HAS_L1CACHE)
##################################################################
# Initialize L1 cache. This must be done after bss clearing
# since the _bss_end symbol may not be cache-line aligned.
##################################################################
.extern __pic32_init_cache
la t0,__pic32_init_cache
jalr t0
nop
#endif
#if defined(INIT_DATA) || defined(__PIC32_HAS_INIT_DATA)
##################################################################
# Initialize data using the linker-generated .dinit table
##################################################################
.extern __pic32_data_init
la t0, __pic32_data_init
jalr t0
nop
#endif /* INIT_DATA */
##################################################################
# If there are no RAM functions, skip the next section --
# initializing bus matrix registers.
##################################################################
la t1,_ramfunc_begin
beqz t1,_ramfunc_done
nop
#if defined(INIT_SSX) || defined(__PIC32_HAS_SSX)
/* No initialization required */
#else /* Use BMX */
##################################################################
# Initialize bus matrix registers if RAM functions exist in the
# application
##################################################################
la t1,_bmxdkpba_address
la t2,BMXDKPBA
sw t1,0(t2)
la t1,_bmxdudba_address
la t2,BMXDUDBA
sw t1,0(t2)
la t1,_bmxdupba_address
la t2,BMXDUPBA
sw t1,0(t2)
#endif /* INIT_SSX */
_ramfunc_done:
##################################################################
# Initialize CP0 registers
##################################################################
# Initialize Count register
##################################################################
mtc0 zero,_CP0_COUNT
##################################################################
# Initialize Compare register
##################################################################
li t2,-1
mtc0 t2,_CP0_COMPARE
##################################################################
# Ensure BEV set and Initialize EBase register
##################################################################
li t0, (1<<22)
mfc0 t2,_CP0_STATUS
or t2,t0,t2 # Set BEV bit 22
mtc0 t2,_CP0_STATUS
la t1,_ebase_address
ehb
mtc0 t1,_CP0_EBASE
##################################################################
# Initialize PRISS register to a safer default for devices that
# have it. The application should re-initialize it to an
# application-specific value.
#
# We do NOT do this by default.
##################################################################
#if defined(USE_DEFAULT_PRISS_VALUE)
#if defined(_PRISS_PRI7SS_POSITION)
#if (PIC32_SRS_SET_COUNT >= 7)
li t2, 0x76540000
addiu t2, t2, 0x3210
lui t1, %hi(PRISS)
sw t2, %lo(PRISS)(t1)
#elif (PIC32_SRS_SET_COUNT <= 2)
li t2, 0x10000000
lui t1, %hi(PRISS)
sw t2, %lo(PRISS)(t1)
#endif /* PIC32_SRS_SET_COUNT */
#endif /* _PRISS_PRI7SS_POSITION */
#endif /* USE_DEFAULT_PRISS_VALUE */
##################################################################
# Initialize IntCtl/INTCON.VS register with _vector_spacing
##################################################################
la t1,_vector_spacing
#if defined(INIT_INTCONVS) || defined(__PIC32_HAS_INTCONVS)
la t0, INTCON
lw t2, 0(t0)
li t2, 0
ins t2, t1, 16, 7
#if defined(__PIC32MM) && defined(_INTCON_MVEC_MASK)
ori t2, t2, _INTCON_MVEC_MASK
#endif
sw t2, 0(t0)
#endif
li t2,0 # Clear t2 and
ins t2,t1,5,5 # shift value to VS field
mtc0 t2,_CP0_INTCTL
##################################################################
# Initialize CAUSE registers
# - Enable counting of Count register <DC = 0>
# - Use special exception vector <IV = 1>
# - Clear pending software interrupts <IP1:IP0 = 0>
##################################################################
li t1,0x00800000
mtc0 t1,_CP0_CAUSE
##################################################################
# Initialize STATUS register
# - Access to Coprocessor 0 not allowed in user mode <CU0 = 0>
# - User mode uses configured endianness <RE = 0>
# - Preserve Bootstrap Exception vectors <BEV>
# - Preserve soft reset <SR> and non-maskable interrupt <NMI>
# - CorExtend enabled based on whether CorExtend User Defined
# Instructions have been implemented <CEE = Config<UDI>>
# - Disable any pending interrupts <IM7..IM2 = 0, IM1..IM0 = 0>
# - Disable hardware interrupts <IPL7:IPL2 = 0>
# - Base mode is Kernel mode <UM = 0>
# - Error level is normal <ERL = 0>
# - Exception level is normal <EXL = 0>
# - Interrupts are disabled <IE = 0>
# - DSPr2 ASE is enabled for devices that support it <MX = 1>
# - FPU64 is enabled for devices that support it <CU1=1> & <FR=1>
##################################################################
mfc0 t0,_CP0_CONFIG
ext t1,t0,22,1 # Extract UDI from Config register
sll t1,t1,17 # Move UDI to Status.CEE location
mfc0 t0,_CP0_STATUS
and t0,t0,0x00580000 # Preserve SR, NMI, and BEV
#if defined(INIT_DSPR2) || defined(__PIC32_HAS_DSPR2)
li t2, 0x01000000 # Set the Status.MX bit to enable DSP
or t0,t2,t0
#endif
#if defined(INIT_FPU64) || defined(__PIC32_HAS_FPU64)
li t2, 0x24000000 # Set the Status.CU1 and Status.FR bits to
or t0,t2,t0 # enable the FPU in FR64 mode
#endif
or t0,t1,t0 # Include Status.CEE (from UDI)
mtc0 t0,_CP0_STATUS
#if defined(PIC32WK) && defined(_CP0_CONFIG3) && defined (__mips_micromips)
# Ensure that the ISAONEXEC bit is set for the microMIPS ISA for the PIC32WK family
# _bsc0 (_CP0_CONFIG3, _CP0_CONFIG3_SELECT, ISAONEXEC_MASK)
li t1,0x10000 # ISAONEXEC bit
mfc0 t0,_CP0_CONFIG3
or t1,t0,t1
mtc0 t1,_CP0_CONFIG3
#endif /* PIC32WK && __mips_micromips */
#if defined(INIT_FPU64) || defined(__PIC32_HAS_FPU64)
# FPU Control and Status
li t2,0x1000000 # FCSR: RM=0, FS=1, FO=0, FN=0
# Enables: 0b00000 E=1, V=0, Z=0, O=0, U=0, I=0
ctc1 t2, $31 # High perf on denormal operands & tiny results
#endif
ehb
##################################################################
# Call the "on bootstrap" procedure
##################################################################
la t0,_on_bootstrap
jalr t0
nop
##################################################################
# Initialize Status<BEV> for normal exception vectors
##################################################################
mfc0 t0,_CP0_STATUS
and t0,t0,0xffbfffff # Clear BEV
mtc0 t0,_CP0_STATUS
##################################################################
# Call main. We do this via a thunk in the text section so that
# a normal jump and link can be used, enabling the startup code
# to work properly whether main is written in MIPS16 or MIPS32
# code. I.e., the linker will correctly adjust the JAL to JALX if
# necessary
##################################################################
and a0,a0,0
and a1,a1,0
la t0,_main_entry
jr t0
nop
.end _startup
##################################################################
# Boot Exception Vector Handler
# Jumps to _bootstrap_exception_handler
##################################################################
.section .bev_handler,code,keep
.align 2
.set noreorder
.ent _bev_exception
_bev_exception:
la k0,_bootstrap_exception_handler
jr k0
nop
.end _bev_exception
##################################################################
# General Exception Vector Handler
# Jumps to _general_exception_context
##################################################################
.section .gen_handler,code
.align 2
.set noreorder
.ent _gen_exception
_gen_exception:
0: la k0,_general_exception_context
jr k0
nop
.end _gen_exception
#if defined(INIT_MMU_MZ_FIXED) || defined(__PIC32_HAS_MMU_MZ_FIXED)
##################################################################
# Simple TLB-Refill Exception Vector
# Jumps to _simple_tlb_refill_exception_context
##################################################################
.section .simple_tlb_refill_vector,code,keep
.align 2
.set noreorder
.ent simple_tlb_refill_vector
simple_tlb_refill_vector:
la k0,_simple_tlb_refill_exception_context
jr k0
nop
.end simple_tlb_refill_vector
#endif
#if defined(INIT_L1_CACHE) || defined(__PIC32_HAS_L1CACHE)
##################################################################
# Cache-Error Exception Vector Handler
# Jumps to _cache_err_exception_context
##################################################################
.section .cache_err_vector,code,keep
.align 2
.set noreorder
.ent _cache_err_vector
_cache_err_vector:
la k0,_cache_err_exception_context
jr k0
nop
.end _cache_err_vector
#endif
.section .text.main_entry,code,keep
.align 2
.ent _main_entry
_main_entry:
#if defined(CPP_INIT)
.weak _init
# call .init section to run constructors etc
lui a0,%hi(_init)
addiu sp,sp,-24
addiu a0,a0,%lo(_init)
beq a0,$0,2f
sw $31,20(sp) #,
jalr a0
nop
2:
#endif
and a0,a0,0
and a1,a1,0
##################################################################
# Call main
##################################################################
la t0,main
jalr t0
nop
#if defined(CALL_EXIT)
##################################################################
# Call exit()
##################################################################
jal exit
nop
#endif
##################################################################
# Just in case, go into infinite loop
# Call a software breakpoint only with -mdebugger compiler option
##################################################################
.weak __exception_handler_break
__crt0_exit:
1:
la v0,__exception_handler_break
beq v0,0,0f
nop
jalr v0
nop
0: b 1b
nop
.globl __crt0_exit
.end _main_entry
Penjelasan
Lihat baris 104 s.d 142. Kode tersebut sebenarnya berkata:
Apakah USE_MIKROE_BOOTLOADER didefinisikan?
│
├── TIDAK
│ │
│ └── STARTUP NORMAL
│ │
│ ├── Jika CPU mendukung MicroMIPS + MIPS32R2 (Baris 107 - 122)
│ │ └── lakukan ISA switching
│ │ jal _startup
│ └── Jika CPU tidak mendukung (Baris 126 - 128)
│ └── jal _startup
└── YA
│
└── STARTUP DENGAN BOOTLOADER MIKROE (Baris 134 - 138)
│
└── la k0,_startup
jr k0Perbedaannya, saat boot normal PC (Program Counter) langsung diarahkan ke alamat startup. Sedangkan saat menggunakan Bootloader MIKROE, alamat startup-nya sudah dipakai bootloader, jadi alamat startup firmware bukan lagi berada di alamat vector startup default. Oleh karena itu simpan alamat startup firmware ke register $k0, baru PC diarahkan ke posisi startup firmware yang tersimpan di $k0.
Jika saat menggunakan bootloader MIKROE PC langsung diarahkan ke alamat startup default, maka yang dijalankan oleh CPU adalah startup Bootloader MIKROE, bukannya startup firmware kita.
NORMAL:
jal _startup
│
└── PC → _startup
DENGAN BOOTLOADER MIKROE:
la k0,_startup
│
└── $k0 → alamat _startup
jr k0
│
└── PC → $k0Ringkasan Perjalanan dari Kode Awal sampai LED Berkedip
1. Kode awal (main.c) Masih template kosong (while(1){}, tidak ada isi).
2. Tulis logika blink di main.c Berdasarkan skema PDF (halaman 10), pin RE0 terhubung lewat resistor R17 (470Ω) ke LD1 — LED merah berlabel “DATA” di board (RE0 tidak muncul di header pinout karena memang dipakai internal untuk LED onboard ini). Ditambahkan:
#include "xc.h"
int main(){
TRISEbits.TRISE0 = 0; // RE0 sebagai output
LATEbits.LATE0 = 0; // mulai LOW
while(1) { LATEbits.LATE0 ^= 1; delay(); } // toggle RE0
}
Ini saja sudah cukup kalau upload pakai programmer eksternal (PICkit/ICD/mikroProg).
3. Masalah muncul jika upload pakai mikroBootloader USB HID. Project XC32/MPLAB X default tidak kompatibel dengan bootloader MikroE, karena startup code (crt0.S) bawaan toolchain melompat ke _startup pakai instruksi jal — sementara bootloader MikroE resident tepat di alamat reset vector (0xBFC00000, dikonfirmasi dari linker script p32MZ1024EFH064.ld).
4. Tambah crt0.S versi override di root project Disalin dari file asli DFP (.mchp_packs\...\xc32\startup\crt0.S), lalu bagian _reset, diubah dari:
_reset:
jal _startup
nop
menjadi far-jump (dibungkus #define USE_MIKROE_BOOTLOADER):
_reset:
la k0, _startup
jr k0
nop
5. Fix linker: tambahkan -nostartfiles Diinjeksikan ke file rule.cmake pada fungsi _default_link_rule, supaya linker tidak lagi menyertakan startup file bawaan toolchain — hanya crt0.S di project yang dipakai.
6. Build sukses .hex dihasilkan → di-upload manual via mikroBootloader
(Connect → Browse for HEX → Begin uploading) → LED RE0 berkedip
Ringkasan
3 perubahan file
— main.c (logika blink),
— crt0.S (baru, far-jump fix),
— rule.cmake (tambah -nostartfiles) di bagian Blink_default_link_rule target
crt0.S (baru, far-jump fix)
