Hi All.
With some theoritical background-help from you experts, I started on building the hello-world program of custom-bootloader.
My setup, includes flashing three binaries to different sections of flash : Bootloader, App1, App2.
Thereafter, I intend to call App1 from Bootloader.
As the first step, I flashed the three binaries to three different non-overlapping regions of flash.
Following were the observations ::
* I flashed "Bootloader". Bootloader worked fine.
* I then flashed "App1" and "App2". Bootloader did not get called.
* I then flashed (again) "Bootloader. It got called fine.
Following are the linker-files of all the 3 binaries ::
Bootloader :
MEMORY
{
FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x00010000
SRAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0X00008000
}
SECTIONS
{
/* code */
.text :
{
_text = .;
/* ensure ISR vectors are not removed by linker */
KEEP(*(.isr_vector))
*(.text*)
*(.rodata*)
_etext = .;
} > FLASH
/* static data */
.data : AT(ADDR(.text) + SIZEOF(.text))
{
_data = .;
*(vtable)
*(.data*)
_edata = .;
} > SRAM
/* static uninitialized data */
.bss :
{
_bss = .;
*(.bss*)
*(COMMON)
_ebss = .;
} > SRAM
}
App1 :
MEMORY
{
FLASH (rx) : ORIGIN = 0x00010001, LENGTH = 0x00020000
SRAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0X00008000
}
SECTIONS
{
/* code */
.text :
{
_text = .;
/* ensure ISR vectors are not removed by linker */
KEEP(*(.isr_vector))
*(.text*)
*(.rodata*)
_etext = .;
} > FLASH
/* static data */
.data : AT(ADDR(.text) + SIZEOF(.text))
{
_data = .;
*(vtable)
*(.data*)
_edata = .;
} > SRAM
/* static uninitialized data */
.bss :
{
_bss = .;
*(.bss*)
*(COMMON)
_ebss = .;
} > SRAM
}
App2 :
MEMORY
{
FLASH (rx) : ORIGIN = 0x00020001, LENGTH = 0x00030000
SRAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0X00008000
}
SECTIONS
{
/* code */
.text :
{
_text = .;
/* ensure ISR vectors are not removed by linker */
KEEP(*(.isr_vector))
*(.text*)
*(.rodata*)
_etext = .;
} > FLASH
/* static data */
.data : AT(ADDR(.text) + SIZEOF(.text))
{
_data = .;
*(vtable)
*(.data*)
_edata = .;
} > SRAM
/* static uninitialized data */
.bss :
{
_bss = .;
*(.bss*)
*(COMMON)
_ebss = .;
} > SRAM
}
As is evident, only the FLASH regions differ.
Also, I am using a common startup-file for compiling each of three binaries.
Following is the relevant section (I believe) ::
static unsigned long pulStack[256];
//*****************************************************************************
//
// The vector table. Note that the proper constructs must be placed on this to
// ensure that it ends up at physical address 0x0000.0000.
//
//*****************************************************************************
__attribute__ ((section(".isr_vector")))
void (* const g_pfnVectors[])(void) =
{
(void (*)(void))((unsigned long)pulStack + sizeof(pulStack)),
// The initial stack pointer
ResetISR, // The reset handler
NmiSR, // The NMI handler
FaultISR, // The hard fault handler
IntDefaultHandler, // The MPU fault handler
IntDefaultHandler, // The bus fault handler
IntDefaultHandler, // The usage fault handler
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
IntDefaultHandler, // SVCall handler
IntDefaultHandler, // Debug monitor handler
0, // Reserved
IntDefaultHandler, // The PendSV handler
IntDefaultHandler, // The SysTick handler
IntDefaultHandler, // GPIO Port A
IntDefaultHandler, // GPIO Port B
IntDefaultHandler, // GPIO Port C
IntDefaultHandler, // GPIO Port D
IntDefaultHandler, // GPIO Port E
IntDefaultHandler, // UART0 Rx and Tx
UART1Handler, // UART1 Rx and Tx
IntDefaultHandler, // SSI0 Rx and Tx
IntDefaultHandler, // I2C0 Master and Slave
IntDefaultHandler, // PWM Fault
IntDefaultHandler, // PWM Generator 0
IntDefaultHandler, // PWM Generator 1
IntDefaultHandler, // PWM Generator 2
IntDefaultHandler, // Quadrature Encoder 0
IntDefaultHandler, // ADC Sequence 0
IntDefaultHandler, // ADC Sequence 1
IntDefaultHandler, // ADC Sequence 2
IntDefaultHandler, // ADC Sequence 3
IntDefaultHandler, // Watchdog timer
IntDefaultHandler, // Timer 0 subtimer A
IntDefaultHandler, // Timer 0 subtimer B
IntDefaultHandler, // Timer 1 subtimer A
IntDefaultHandler, // Timer 1 subtimer B
IntDefaultHandler, // Timer 2 subtimer A
IntDefaultHandler, // Timer 2 subtimer B
IntDefaultHandler, // Analog Comparator 0
IntDefaultHandler, // Analog Comparator 1
IntDefaultHandler, // Analog Comparator 2
IntDefaultHandler, // System Control (PLL, OSC, BO)
IntDefaultHandler, // FLASH Control
IntDefaultHandler, // GPIO Port F
IntDefaultHandler, // GPIO Port G
IntDefaultHandler, // GPIO Port H
IntDefaultHandler, // UART2 Rx and Tx
IntDefaultHandler, // SSI1 Rx and Tx
IntDefaultHandler, // Timer 3 subtimer A
IntDefaultHandler, // Timer 3 subtimer B
IntDefaultHandler, // I2C1 Master and Slave
IntDefaultHandler, // Quadrature Encoder 1
IntDefaultHandler, // CAN0
IntDefaultHandler, // CAN1
IntDefaultHandler, // CAN2
IntDefaultHandler, // Ethernet
IntDefaultHandler, // Hibernate
IntDefaultHandler, // USB0
IntDefaultHandler, // PWM Generator 3
IntDefaultHandler, // uDMA Software Transfer
IntDefaultHandler, // uDMA Error
IntDefaultHandler, // ADC1 Sequence 0
IntDefaultHandler, // ADC1 Sequence 1
IntDefaultHandler, // ADC1 Sequence 2
IntDefaultHandler, // ADC1 Sequence 3
IntDefaultHandler, // I2S0
IntDefaultHandler, // External Bus Interface 0
IntDefaultHandler, // GPIO Port J
IntDefaultHandler, // GPIO Port K
IntDefaultHandler, // GPIO Port L
IntDefaultHandler, // SSI2 Rx and Tx
IntDefaultHandler, // SSI3 Rx and Tx
#ifdef GPS_INTERFACE_ENABLED
UART3Handler, // UART3 Rx and Tx
#else
IntDefaultHandler, // UART3 Rx and Tx
#endif
IntDefaultHandler, // UART4 Rx and Tx
IntDefaultHandler, // UART5 Rx and Tx
#ifdef MODBUS_INTERFACE_ENABLED
UART6Handler, // UART6 Rx and Tx
#else
IntDefaultHandler, // UART6 Rx and Tx
#endif
IntDefaultHandler, // UART7 Rx and Tx
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
IntDefaultHandler, // I2C2 Master and Slave
IntDefaultHandler, // I2C3 Master and Slave
IntDefaultHandler, // Timer 4 subtimer A
IntDefaultHandler, // Timer 4 subtimer B
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
IntDefaultHandler, // Timer 5 subtimer A
IntDefaultHandler, // Timer 5 subtimer B
IntDefaultHandler, // Wide Timer 0 subtimer A
IntDefaultHandler, // Wide Timer 0 subtimer B
IntDefaultHandler, // Wide Timer 1 subtimer A
IntDefaultHandler, // Wide Timer 1 subtimer B
IntDefaultHandler, // Wide Timer 2 subtimer A
IntDefaultHandler, // Wide Timer 2 subtimer B
IntDefaultHandler, // Wide Timer 3 subtimer A
IntDefaultHandler, // Wide Timer 3 subtimer B
IntDefaultHandler, // Wide Timer 4 subtimer A
IntDefaultHandler, // Wide Timer 4 subtimer B
IntDefaultHandler, // Wide Timer 5 subtimer A
IntDefaultHandler, // Wide Timer 5 subtimer B
IntDefaultHandler, // FPU
IntDefaultHandler, // PECI 0
IntDefaultHandler, // LPC 0
IntDefaultHandler, // I2C4 Master and Slave
IntDefaultHandler, // I2C5 Master and Slave
IntDefaultHandler, // GPIO Port M
IntDefaultHandler, // GPIO Port N
IntDefaultHandler, // Quadrature Encoder 2
IntDefaultHandler, // Fan 0
0, // Reserved
IntDefaultHandler, // GPIO Port P (Summary or P0)
IntDefaultHandler, // GPIO Port P1
IntDefaultHandler, // GPIO Port P2
IntDefaultHandler, // GPIO Port P3
IntDefaultHandler, // GPIO Port P4
IntDefaultHandler, // GPIO Port P5
IntDefaultHandler, // GPIO Port P6
IntDefaultHandler, // GPIO Port P7
IntDefaultHandler, // GPIO Port Q (Summary or Q0)
IntDefaultHandler, // GPIO Port Q1
IntDefaultHandler, // GPIO Port Q2
IntDefaultHandler, // GPIO Port Q3
IntDefaultHandler, // GPIO Port Q4
IntDefaultHandler, // GPIO Port Q5
IntDefaultHandler, // GPIO Port Q6
IntDefaultHandler, // GPIO Port Q7
IntDefaultHandler, // GPIO Port R
IntDefaultHandler, // GPIO Port S
IntDefaultHandler, // PWM 1 Generator 0
IntDefaultHandler, // PWM 1 Generator 1
IntDefaultHandler, // PWM 1 Generator 2
IntDefaultHandler, // PWM 1 Generator 3
IntDefaultHandler // PWM 1 Fault
};
SInce all three binaries are flashed in different regions (with "Bootloader") being at the "starting location", Bootloader must always be called, irrespective of whether any other binary is flashed or not (of course, as long as it does not over-write the "Bootloader" binary).
Unfortunately, above is not happening.
Where am I being foolish? Will be grateful for pointers.
Thanks and Regards,
Ajay
