Kami akan mencemooh sirkuit mikro GD32VF103CBT6, yang merupakan analog dari STM32F103 yang terkenal, dengan perbedaan kecil namun penting: alih-alih inti ARM, ia menggunakan inti RISC-V. Bagaimana itu mengancam kita, sebagai programmer, mari kita coba mencari tahu.
Secara singkat saya akan mencantumkan karakteristik pengontrol:
• Tegangan suplai: 2,6 - 3,6 V
• Frekuensi clock maksimum: 108 MHz
• Ukuran ROM (flash): 128 kB
• Ukuran RAM (ram): 32 kB
• Ukuran register cadangan (disimpan setelah reset): 42 x 16 bit = 84 byte.
• ADC + DAC: 2 buah ADC dengan 10 saluran dan 12 bit masing-masing ditambah 2 DAC dari 12 bit.
• Tentu saja, banyak periferal lain seperti timer, SPI, I2C, UART, dll.
, — … , , .
, , : https://github.com/COKPOWEHEU/GD32VF103_tutor
-1.
— . -, : , , ? . -, . , UART. , , .
— , , , ( PA0 — PA7 , PB8 — PB15 ). usb (, usb-uart), , , 3.3 .
UART, . «» , , Rx Tx. « » , .
, Boot0 Boot1 .
.
0.
IDE. : , .
. , , GigaDevice .
| gcc-riscv64-unknown-elf | |
| stm32flash, dfu-util | bootloader |
| kicad | |
| screen | UART |
. :
(1). JTAG — , .
(2). Bootloader.UART — Boot0 , ( , ), stm32flash (, , !)
$ stm32flash /dev/ttyUSB0 -w firmware.bin
Boot0 , ( )
(3). Bootloader.USB — , stm32flash dfu-util:
$ dfu-util -a 0 -d 28e9:0189 -s 0x08000000 -D firmware.bin
, USB , RC-, USB .
, dfu-util . - . , . Boot0 , Bootloader, Boot1. , .
0,5. ?
stm32f103 . , SPI DMA ( !) .
, GigaDevice , STMicroelectronics, . . :
| GD32VF103 | STM32F103 |
|---|---|
| RCU_APB2EN |= RCU_APB2EN_SPI0EN; | RCC->APB2ENR |= RCC_APB2ENR_SPI1EN; |
| SPI_DATA(SPI_NAME) = data; | SPI1->DR = data; |
| DMA_CHCNT(LCD_DMA, LCD_DMA_CHAN) = size; | DMA1_Channel3->CNDTR = size; |
RISCV SPI_DATA , SPI. ! - SPI0, DMA0 2 .
(https://habr.com/ru/post/496046/ : https://github.com/COKPOWEHEU/stm32f103_ili9341_models3D) :
: https://github.com/COKPOWEHEU/RISCV-ili9341-3D
1.
, -, — , — . ( , !).
. , -, . RCU_APB2EN ( 0x40021018) RCU_APB2EN_PxEN, x — . , PB5 — PB7 RCU_APB2EN_PBEN (3- , 0x8). .
la a5, 0x40021018 lw a4, 0(a5) ori a4, a4, 8 sw a4, 0(a5)
a4, a5 , . .
, . , :
.equ RCU_APB2EN, 0x40021018 .equ RCU_APB2EN_PBEN, (1<<3) //RCU_APB2EN |= RCU_APB2EN_PBEN la a5, RCU_APB2EN lw a4, 0(a5) ori a4, a4, RCU_APB2EN_PBEN sw a4, 0(a5)
. - , - , . , GPIO_CTL. - 16, 64 , 32-. STmicroelectronics . B GPIOB_CTL0 GPIOB_CTL1: PB0 — PB7, PB8 — PB15. 16 , ( ). , 5 — 7 , 0 1:
.equ GPIOB_CTL0, 0x40010C00 .equ GPIO_MASK, 0b1111 .equ GPIO_PP_50MHz, 0b0011 .equ RLED, 5 .equ YLED, 6 .equ GLED, 7 .equ SBTN, 0 .equ RBTN, 1
, 4 GPIOB_CTL0: [0, 1, 2, 3], [4, 5, 6, 7]. , 5- , , [20, 21, 22, 23]. , . , :
GPIOB_CTL0 = (GPIOB_CTL0 &~(0b1111<<(RLED*4))) | 0b0011 << (RLED*4);
4 , . , , :
la a5, GPIOB_CTL0 lw a4, 0(a5) la a6, ~(GPIO_MASK << (RLED*4)) and a3, a4, a6 la a4, (GPIO_PP_50MHz << (RLED*4)) or a4, a4, a3 sw a4, 0(a5)
. , . 0 1, - . GPIOB_OCTL, , XOR` 5- . .
.equ RCU_APB2EN, 0x40021018 .equ RCU_APB2EN_PBEN, (1<<3) .equ GPIOB_CTL0, 0x40010C00 .equ GPIO_MASK, 0b1111 .equ GPIO_PP_50MHz, 0b0011 .equ GPIOB_OCTL, 0x40010C0C .equ RLED, 5 .equ YLED, 6 .equ GLED, 7 .equ SBTN, 0 .equ RBTN, 1 .text .global _start _start: //RCU_APB2EN |= RCU_APB2EN_PBEN la a5, RCU_APB2EN lw a4, 0(a5) ori a4, a4, RCU_APB2EN_PBEN sw a4, 0(a5) //GPIOB_CTL0 = (GPIOB_CTL0 & (0b1111<<RLED*4)) | 0b0011 << (RLED*4) la a5, GPIOB_CTL0 lw a4, 0(a5) la a6, ~(GPIO_MASK << (RLED*4)) and a3, a4, a6 la a4, (GPIO_PP_50MHz << (RLED*4)) or a4, a4, a3 sw a4, 0(a5) MAIN_LOOP: //GPIO_OCTL(GPIOB) ^= (1<<RLED) la a5, GPIOB_OCTL lw a4, 0(a5) xori a4, a4, (1<<RLED) sw a4, 0(a5) //sleep la a5, 200000 sleep: addi a5, a5, -1 bnez a5, sleep j MAIN_LOOP
200000 . .
, OCTL , --. ( ), . GPIOx_BOP: 16 OCTL 0, — 1. GPIOx_BC, BOP, . . , . .
.equ GPIOB_BOP, 0x40010C10 … la a5, GPIOB_BOP la a4, (1<<YLED) | (1<<RLED*16) sw a4, 0(a5)
, .
, , OCTL`.
gcc:
$ riscv64-unknown-elf-gcc -march=rv32imac -mabi=ilp32 -mcmodel=medany -nostdlib main.S -o main.elf
, -nostdlib ( ) ` . . , , ( , ), :
$ riscv64-unknown-elf-objcopy -O binary main.elf main.bin $ riscv64-unknown-elf-objdump -D -S main.elf > main.lss $ stm32flash /dev/ttyUSB0 -w main.bin
makefile.
, COM USB . , , dialout. USB dfu-utils, udev 28e9:0189.
2.
- , GPIOB_ISTAT, , . . , :
.equ GPIO_MASK, 0b1111 # #input .equ GPIO_ANALOG, 0b0000 # .equ GPIO_HIZ, 0b0100 # .equ GPIO_PULL, 0b1000 # .equ GPIO_RESERVED, 0b1100 # , #output, GPIO, .equ GPIO_PP10, 0b0001 # push-pull , 10 .equ GPIO_PP2, 0b0010 # -//- 2 .equ GPIO_PP50, 0b0011 # -//- 50 .equ GPIO_OD10, 0b0101 # open-drain , 10 .equ GPIO_OD2, 0b0110 # -//- 2 .equ GPIO_OD50, 0b0111 # -//- 50 #output, AFIO — , .equ GPIO_APP10, 0b1001 # push-pull , 10 .equ GPIO_APP2, 0b1010 # -//- 2 .equ GPIO_APP50, 0b1011 # -//- 50 .equ GPIO_AOD10, 0b1101 # open-drain , 10 .equ GPIO_AOD2, 0b1110 # -//- 2 .equ GPIO_AOD50, 0b1111 # -//- 50
push-pull , , . 0, 1 GPIOx_OCTL. open-drain , , . 0, . « » , , I2C . OCTL. pull-up, pull-down , (pull-up), (pull-down). GPIOx_OCTL. . , . , . .
3.
. . , . , . :
| zero | x0 | n/a | |
| ra | x1 | ||
| sp | x2 | Stack pointer, | |
| gp, tp | x3, x4 | . | n/a |
| t0-t6 | x5-x7, x28-x31 | ||
| s0-s11 | x8, x9, x18-x27 | ||
| a0-a7 | x10-x17 | ||
| a0, a1 | x10, x11 |
zero , , . /dev/zero /dev/null
ra sp - .
gp tp . , . , .
t0 — t6 . , .
s0 — s11 . — - .
a0 — a7 . , , . , a0 a1, .
, , . 200`000 , . . ( ) . , a0. a1 — a7 t0 — t6, . , .
, , . ? ra, (jal, jalr call, ) , . , , , ra jr ra ret. , a5 a0:
... la a0, 200000 call sleep ... sleep: addi a0, a0, -1 bnez a0, sleep ret
4.
, ? , . , ?
, , , . , , - . : , , , , — , . . , , .
, .
: , . sp. GD32VF103 0x2000'0000 32 , 0x2000'8000, .
, 0x12, 0x34 0x56, . :
| 0 | 1 | 2 | 3 | 4 | |
|---|---|---|---|---|---|
| 0x2000`8000 | ← sp | ||||
| 0x2000`7FFF | 0x12 ← sp | 0x12 | 0x12 | 0x12 | |
| 0x2000`7FFE | 0x34 ← sp | 0x34 | 0x34 ← sp | ||
| 0x2000`7FFD | 0x56 ← sp |
, 4 0x56 , «» .
, . , RISC-V , . , , 4- 0x2000'0002 — 0x2000'0000 0x2000'0004. , — , 4-, 4- .
— . , . , , , . , sp. , ( ) . , , , , . : ( sp) . : — sp.
, :
.macro push val addi sp, sp, -4 sw \val, 0(sp) .endm .macro pop val lw \val, 0(sp) addi sp, sp, 4 .endm
, sp :
la sp, 0x20008000
, sleep -, :
sleep: push ra push s0 mv s0, a0 sleep_loop: addi s0, s0, -1 bnez s0, sleep_loop pop s0 pop ra ret
, sleep : a0. … , ! - . , , . , .
push pop, , sp 4 . ! - . , , , , sp. , :
func: addi sp, sp, -16 sw ra, 12(sp) sw s0, 8(sp) sw s1, 4(sp) sw s2, 0(sp) … lw s2, 0(sp) lw s1, 4(sp) lw s0, 8(sp) lw ra, 12(sp) addi sp, sp, 16 ret
, «» , , , , , . — sp , sp . , fp — frame pointer ( s0, ). sp, . sp, , , fp , .
, 5 ra, fp , , s1, s2 s3. :
func: addi sp, sp, -10*4 sw fp, 0(sp) addi fp, sp, 10*4 sw ra, -9*4(fp) sw s1, -8*4(fp) sw s2, -7*4(fp) sw s3, -6*4(fp) sw zero, -5*4(fp) # — data[0] sw zero, -4*4(fp) # — data[1] sw zero, -3*4(fp) # — data[2] sw zero, -2*4(fp) # — data[3] sw zero, -1*4(fp) # — data[4] … lw s3, -6*4(fp) lw s2, -7*4(fp) lw s1, -8*4(fp) lw ra, -9*4(fp) addi sp, fp, -10*4 lw fp, 0(sp) addi sp, sp, 10*4 ret
- ( ), . sp fp, . , push' pop' , , .
, fp . sp, fp s0.
5.
, . , .
— . -, . .rodata, . 4 :
.text led_arr: .short (0<<GLED | 0<<YLED | 1<<RLED) .short (0<<GLED | 1<<YLED | 0<<RLED) .short (1<<GLED | 0<<YLED | 0<<RLED) .short (0<<GLED | 1<<YLED | 0<<RLED) led_arr_end:
.short , — 2 . .
:
MAIN_LOOP: la s0, GPIOB_OCTL lh s1, 0(s0) la s2, ~(1<<GLED | 1<<YLED | 1<<RLED) la s3, led_arr la s4, led_arr_end led_loop: lh t0, 0(s3) and s1, s1, s2 or s1, s1, t0 sh s1, 0(s0) la a0, 300000 call sleep addi s3, s3, 2 bltu s3, s4, led_loop j MAIN_LOOP
. -, lw lh GPIOB_OCTL. 2-, GPIOB_OCTL, , . -, 1, . 32- , 4 , — 1.
6.
.rodata, .text. : .data .bss. , , — . .bss : , — , . , .
, .text .data, . res/firmware.lss , 0x2000'0000:
000110ea <__DATA_BEGIN__>: 110ea: 0020
, - . , . , lib/gd32vf103cbt6.ld, :
MEMORY{ flash (rxai!w) : ORIGIN = 0x00000000, LENGTH = 128K ram (wxa!ri) : ORIGIN = 0x20000000, LENGTH = 32K } SECTIONS{ .text : { } > flash .data : { } > ram .bss : { } > ram }
, . (, ) -T:
riscv64-unknown-elf-gcc -march=rv32imac -mabi=ilp32 -mcmodel=medany -nostdlib -T lib/gd32vf103cbt6.ld src/main.S -o res/main.elf
, :
20000000 <led_arr>: 20000000: 0020
, , , . , . .text, res/firmware.hex .
:08 0000 00 2000 4000 8000 4000 D8
.ld-
MEMORY{ flash (rxai!w) : ORIGIN = 0x00000000, LENGTH = 128K ram (wxa!ri) : ORIGIN = 0x20000000, LENGTH = 32K } SECTIONS{ .text : { *(.text*) *(.rodata*) . = ALIGN(4); } > flash .data : AT(ADDR(.text) + SIZEOF(.text)){ _data_start = .; *(.data*) . = ALIGN(4); _data_end = .; } > ram .bss : { _bss_start = .; *(.bss*) . = ALIGN(4); _bss_end = .; } > ram } PROVIDE(_stack_end = ORIGIN(ram) + LENGTH(ram)); PROVIDE(_data_load = LOADADDR(.data));
- _data_load . , , :
_start: la sp, _stack_end #copy data section la a0, _data_load la a1, _data_start la a2, _data_end bgeu a1, a2, copy_data_end copy_data_loop: lw t0, (a0) sw t0, (a1) addi a0, a0, 4 addi a1, a1, 4 bltu a1, a2, copy_data_loop copy_data_end: # Clear [bss] section la a0, _bss_start la a1, _bss_end bgeu a0, a1, clear_bss_end clear_bss_loop: sw zero, (a0) addi a0, a0, 4 bltu a0, a1, clear_bss_loop clear_bss_end:
Sekarang, akhirnya, array kita akan terbaca dengan benar dari RAM.
Saat membuat variabel di bagian .bss, akan aneh untuk menetapkan nilai apa pun (meskipun tidak ada yang melarangnya, mereka tidak akan digunakan). Anda dapat menggunakan .comm arr, 10 placeholder directive (untuk variabel arr 10 byte) sebagai gantinya. Perlu dicatat bahwa ini dapat digunakan di bagian mana pun, dan hanya akan mencadangkan data dalam .bss. Di bawah ini adalah lebih banyak contoh mendeklarasikan variabel dengan berbagai ukuran:
.byte 1, 2, 3 # 0x01, 0x02 0x03 .short 4, 5 # 0x0004 0x0005 .word 6, 7 # 0x0000'0006 0x0000'0007 .quad 100500 # 0x0000'0000'0001'8894 .ascii "abcd", "efgh" # 4 ( ! ) .asciz "1234" # "1234\0" - . 'i' .space 10, 20 # 10 , 20. ,
Tiba-tiba berakhir
Saya tidak ingin membagi artikel menjadi dua, tetapi apa yang harus saya lakukan. Di bagian selanjutnya, kita akan melihat cara bekerja dengan port debug UART, dengan interupsi, dan cara menggabungkan bahasa assembly dan kode C.