I'm trying to program a usb connection in riscv assembler on the pico2 starting from the example dev_lowlevel.c and of course without using the SDK.
In this example, we don't see where the interrupt management function is called so I dived into the documentation chapter 3.8.4 and examined the assembler generated for this example.
In my program, I put the function irq_set_enabled with the parameter = 14 (IRQ USB)
I created a table __VECTOR_TABLE in .data aligned on 64 bits and which contains:Following the function:
isr_riscv_machine_external_irq: identical to that found in the example
I put the address of this table +1 in the register mtvec and set the bits in the registers mstatus, MIE and MIP with the values below :I also created a 32-bit aligned __soft_vector_table whose position (14 * 4) contains the address of my interrupt handling function.
But the isr_riscv_machine_external_irq function never seems to be called when I plug the pico into my computer's USB port. W11 tells me that the device has malfunctioned!!
I must have forgotten something but what?
In this example, we don't see where the interrupt management function is called so I dived into the documentation chapter 3.8.4 and examined the assembler generated for this example.
In my program, I put the function irq_set_enabled with the parameter = 14 (IRQ USB)
I created a table __VECTOR_TABLE in .data aligned on 64 bits and which contains:
Code:
__VECTOR_TABLE: j arret10Eclats .skip 8 j arret10Eclats .skip 12 j arret10Eclats .skip 12 j arret10Eclats #j isr_riscv_machine_external_irq isr_riscv_machine_external_irq: identical to that found in the example
I put the address of this table +1 in the register mtvec and set the bits in the registers mstatus, MIE and MIP with the values below :
Code:
laa0,__VECTOR_TABLE + 1 # voir 3.8 csrwmtvec,a0 li t0,0b10001000 csrs 0x300,t0 # 1 dans MSTATUS.MIE li t0,0b100000000000 csrs 0x344,t0 # 1 bit MEIP MIP Register csrs 0x304,t0 # 1 bit MEIP MIE RegisterBut the isr_riscv_machine_external_irq function never seems to be called when I plug the pico into my computer's USB port. W11 tells me that the device has malfunctioned!!
I must have forgotten something but what?
Statistics: Posted by VincentARM — Sun Jan 19, 2025 8:53 pm
