From 261c210c9c4c1e55103a7af31dfcc539c0e0e5cc Mon Sep 17 00:00:00 2001 From: Jacques Comeaux Date: Fri, 19 Jan 2024 16:41:29 -0600 Subject: Add subroutine for printing hexadecimal word --- hexedit/Makefile | 17 +++++++ hexedit/clocks.s | 31 +++++++++++++ hexedit/gpio.s | 23 ++++++++++ hexedit/hexedit.s | 25 ++++++++++ hexedit/main.s | 16 +++++++ hexedit/pico_ram_only.ld | 13 ++++++ hexedit/uart.s | 116 +++++++++++++++++++++++++++++++++++++++++++++++ hexedit/xosc.s | 23 ++++++++++ 8 files changed, 264 insertions(+) create mode 100644 hexedit/Makefile create mode 100644 hexedit/clocks.s create mode 100644 hexedit/gpio.s create mode 100644 hexedit/hexedit.s create mode 100644 hexedit/main.s create mode 100644 hexedit/pico_ram_only.ld create mode 100644 hexedit/uart.s create mode 100644 hexedit/xosc.s (limited to 'hexedit') diff --git a/hexedit/Makefile b/hexedit/Makefile new file mode 100644 index 0000000..95f49ae --- /dev/null +++ b/hexedit/Makefile @@ -0,0 +1,17 @@ +all: build + +build: echo.uf2 + +echo.uf2: echo.elf + ../elf/elf2uf2 echo.elf echo.uf2 + +objects = main.o xosc.o clocks.o gpio.o uart.o + +echo.elf: $(objects) + arm-none-eabi-ld -T pico_ram_only.ld -o echo.elf $(objects) + +$(objects): %.o: %.s + arm-none-eabi-as -o $@ $< + +clean: + rm echo.elf echo.uf2 *.o diff --git a/hexedit/clocks.s b/hexedit/clocks.s new file mode 100644 index 0000000..83bc9ff --- /dev/null +++ b/hexedit/clocks.s @@ -0,0 +1,31 @@ +.syntax unified +.cpu cortex-m0plus +.thumb + +.equ CLOCKS_BASE, 0x40008000 +.equ CLK_REF_CTRL_OFST, 0x30 +.equ CLK_SYS_CTRL_OFST, 0x3c +.equ CLK_PERI_CTRL_OFST, 0x48 + +.type setup_clocks, %function +.global setup_clocks + +setup_clocks: + + ldr r1, =CLOCKS_BASE + + // Reference clock + movs r0, 0x2 // src = xosc + str r0, [r1, CLK_REF_CTRL_OFST] + + // System clock + movs r0, 0x0 // src = clk_ref + str r0, [r1, CLK_SYS_CTRL_OFST] + + // Peripheral clock + movs r0, 1 // set enable + lsls r0, 11 + adds r0, 0x4 << 5 // src = xosc + str r0, [r1, CLK_PERI_CTRL_OFST] + + bx lr diff --git a/hexedit/gpio.s b/hexedit/gpio.s new file mode 100644 index 0000000..32e2c37 --- /dev/null +++ b/hexedit/gpio.s @@ -0,0 +1,23 @@ +.syntax unified +.cpu cortex-m0plus +.thumb + +.equ RESETS_BASE, 0x4000c000 +.equ RESET_OFST, 0x0 +.equ RESET_DONE_OFST, 0x8 + +.equ ATOMIC_CLEAR, 0x3000 + +.type setup_gpio, %function +.global setup_gpio + +setup_gpio: + ldr r1, =(RESETS_BASE + ATOMIC_CLEAR) + movs r0, 0b1 << 5 // IO_BANK0 + str r0, [r1, RESET_OFST] + ldr r1, =RESETS_BASE +1: + ldr r2, [r1, RESET_DONE_OFST] + tst r2, r0 + beq 1b + bx lr diff --git a/hexedit/hexedit.s b/hexedit/hexedit.s new file mode 100644 index 0000000..0bc03a9 --- /dev/null +++ b/hexedit/hexedit.s @@ -0,0 +1,25 @@ +.syntax unified +.cpu cortex-m0plus +.thumb + +.type hexedit, %function +.global hexedit + +hexedit: + ldr r2, =0x20000100 + movs r1, 0 +getchar: + bl uart_recv + cmp r0, 'g + beq stop + subs r0, '0 // The ASCII char '0' + bmi next + lsls r1, 4 + adds r1, r0 + b getchar +next: + ldr r0, [r2, 0] + adds r2, 4 + b hexedit +stop: + b 0x20000100 diff --git a/hexedit/main.s b/hexedit/main.s new file mode 100644 index 0000000..5e294d4 --- /dev/null +++ b/hexedit/main.s @@ -0,0 +1,16 @@ +.syntax unified +.cpu cortex-m0plus +.thumb + +.type main, %function +.global main + +main: + bl start_xosc + bl setup_clocks + bl setup_gpio + bl setup_uart +1: + bl uart_recv + bl uart_send + b 1b diff --git a/hexedit/pico_ram_only.ld b/hexedit/pico_ram_only.ld new file mode 100644 index 0000000..eb2450e --- /dev/null +++ b/hexedit/pico_ram_only.ld @@ -0,0 +1,13 @@ +ENTRY(main) + +MEMORY { + FLASH(rx) : ORIGIN = 0x10000000, LENGTH = 2M + SRAM(rwx) : ORIGIN = 0x20000000, LENGTH = 264K +} + +SECTIONS { + .text : { + *(.text) + . = ALIGN(4); + } > SRAM +} diff --git a/hexedit/uart.s b/hexedit/uart.s new file mode 100644 index 0000000..9804e53 --- /dev/null +++ b/hexedit/uart.s @@ -0,0 +1,116 @@ +.syntax unified +.cpu cortex-m0plus +.thumb + +.equ RESETS_BASE, 0x4000c000 +.equ RESET_OFST, 0x0 +.equ RESET_DONE_OFST, 0x8 + +.equ IO_BANK0_BASE, 0x40014000 +.equ GPIO0_CTRL_OFST, 0x04 +.equ GPIO1_CTRL_OFST, 0x0c + +.equ UART0_BASE, 0x40034000 +.equ UARTDR_OFST, 0x00 +.equ UARTFR_OFST, 0x18 +.equ UARTIBRD_OFST, 0x24 +.equ UARTFBRD_OFST, 0x28 +.equ UARTLCR_H_OFST, 0x2c +.equ UARTCR_OFST, 0x30 + +.equ ATOMIC_SET, 0x2000 +.equ ATOMIC_CLEAR, 0x3000 + +.type setup_uart, %function +.global setup_uart + +setup_uart: + + // Deassert reset + ldr r1, =(RESETS_BASE + ATOMIC_CLEAR) + movs r0, 0b1 // UART0 + lsls r0, 22 + str r0, [r1, RESET_OFST] + ldr r1, =RESETS_BASE +1: + ldr r2, [r1, RESET_DONE_OFST] + tst r2, r0 + beq 1b + + // Configure and enable + ldr r1, =UART0_BASE + movs r0, 6 + str r0, [r1, UARTIBRD_OFST] + movs r0, 33 + str r0, [r1, UARTFBRD_OFST] + movs r0, 0b111 << 4 // 0b11 = word len 8 bits, 0b1 = FIFO enabled + str r0, [r1, UARTLCR_H_OFST] + ldr r1, =(UART0_BASE + ATOMIC_SET) + movs r0, 0b1 // UART enable + str r0, [r1, UARTCR_OFST] + + // Configure GPIO 0 and 1 as TX and RX + ldr r1, =IO_BANK0_BASE + movs r0, 2 // UART function + str r0, [r1, GPIO0_CTRL_OFST] + str r0, [r1, GPIO1_CTRL_OFST] + + bx lr + +.type uart_send, %function +.global uart_send + +uart_send: + ldr r1, =UART0_BASE + movs r3, 0b1 << 5 // TX FIFO full +1: + ldr r2, [r1, UARTFR_OFST] + tst r2, r3 + bne 1b + strb r0, [r1, UARTDR_OFST] + bx lr + +.type uart_recv, %function +.global uart_recv + +uart_recv: + ldr r1, =UART0_BASE + movs r3, 0b1 << 4 // RX FIFO empty +1: + ldr r2, [r1, UARTFR_OFST] + tst r2, r3 + bne 1b + ldrb r0, [r1, UARTDR_OFST] + bx lr + +.type send_hex, %function +.global send_hex + +send_hex: + push {lr} + movs r4, r0 + movs r0, '0 + bl uart_send + movs r0, 'x + bl uart_send + movs r5, 8 // eight nibbles in a word +0: + movs r0, 28 // rotate left 4 + rors r4, r0 + movs r0, 0xF // lowest nibble mask + ands r0, r4 + cmp r0, 0x9 // number or letter? + bhi 1f + adds r0, '0 + b 2f +1: + adds r0, 'A - 0xA +2: + bl uart_send + subs r5, 1 + bne 0b + movs r0, '\r + bl uart_send + movs r0, '\n + bl uart_send + pop {pc} diff --git a/hexedit/xosc.s b/hexedit/xosc.s new file mode 100644 index 0000000..63760da --- /dev/null +++ b/hexedit/xosc.s @@ -0,0 +1,23 @@ +.syntax unified +.cpu cortex-m0plus +.thumb + +.equ XOSC_BASE, 0x40024000 +.equ CTRL_OFST, 0x0 +.equ STATUS_OFST, 0x4 +.equ STARTUP_OFST, 0xc + +.type start_xosc, %function +.global start_xosc + +start_xosc: + ldr r1, =XOSC_BASE + movs r0, 47 // startup delay for 12Mhz crystal + str r0, [r1, STARTUP_OFST] + ldr r0, =0x00fabaa0 // enable + str r0, [r1, CTRL_OFST] +1: + ldr r0, [r1, STATUS_OFST] + lsrs r0, 31 // stable bit + beq 1b + bx lr -- cgit v1.2.3