使用 PIO 串口（还未测试）

2024-03-31 18:04:35 +08:00
parent d329c022b5
commit 7f9fc40757
7 changed files with 443 additions and 14 deletions
--- a/uart_tx.pio.h
+++ b/uart_tx.pio.h
@@ -0,0 +1,78 @@
+// -------------------------------------------------- //
+// This file is autogenerated by pioasm; do not edit! //
+// -------------------------------------------------- //
+
+#pragma once
+
+#if !PICO_NO_HARDWARE
+#include "hardware/pio.h"
+#endif
+
+// ------- //
+// uart_tx //
+// ------- //
+
+#define uart_tx_wrap_target 0
+#define uart_tx_wrap 3
+
+static const uint16_t uart_tx_program_instructions[] = {
+    //     .wrap_target
+    0x9fa0,                     //  0: pull   block           side 1 [7] 
+    0xf727,                     //  1: set    x, 7            side 0 [7] 
+    0x6001,                     //  2: out    pins, 1                    
+    0x0642,                     //  3: jmp    x--, 2                 [6] 
+    //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program uart_tx_program = {
+    .instructions = uart_tx_program_instructions,
+    .length = 4,
+    .origin = -1,
+};
+
+static inline pio_sm_config uart_tx_program_get_default_config(uint offset)
+{
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + uart_tx_wrap_target, offset + uart_tx_wrap);
+    sm_config_set_sideset(&c, 2, true, false);
+    return c;
+}
+
+#include "hardware/clocks.h"
+static inline void uart_tx_program_init(PIO pio, uint sm, uint offset, uint pin_tx, uint baud)
+{
+    // Tell PIO to initially drive output-high on the selected pin, then map PIO
+    // onto that pin with the IO muxes.
+    pio_sm_set_pins_with_mask(pio, sm, 1u << pin_tx, 1u << pin_tx);
+    pio_sm_set_pindirs_with_mask(pio, sm, 1u << pin_tx, 1u << pin_tx);
+    pio_gpio_init(pio, pin_tx);
+    pio_sm_config c = uart_tx_program_get_default_config(offset);
+    // OUT shifts to right, no autopull
+    sm_config_set_out_shift(&c, true, false, 32);
+    // We are mapping both OUT and side-set to the same pin, because sometimes
+    // we need to assert user data onto the pin (with OUT) and sometimes
+    // assert constant values (start/stop bit)
+    sm_config_set_out_pins(&c, pin_tx, 1);
+    sm_config_set_sideset_pins(&c, pin_tx);
+    // We only need TX, so get an 8-deep FIFO!
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+    // SM transmits 1 bit per 8 execution cycles.
+    float div = (float)clock_get_hz(clk_sys) / (8 * baud);
+    sm_config_set_clkdiv(&c, div);
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+}
+
+static inline void uart_tx_program_putc(PIO pio, uint sm, char c)
+{
+    pio_sm_put_blocking(pio, sm, (uint32_t) c);
+}
+
+static inline void uart_tx_program_puts(PIO pio, uint sm, const char *s)
+{
+    while (*s)
+        uart_tx_program_putc(pio, sm, *s++);
+}
+
+#endif