在nexys4 ddr上使用platformio开发时串口输出始终为空

Question

目标

通过串口输出“Hello world”

platform.ini 配置

; PlatformIO Project Configuration File
;
;   Build options: build flags, source filter
;   Upload options: custom upload port, speed and extra flags
;   Library options: dependencies, extra library storages
;   Advanced options: extra scripting
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html

[env:swervolf_nexys]
platform = chipsalliance
board = swervolf_nexys
framework = wd-riscv-sdk

monitor_speed = 115200

board_build.bitstream_file = ./rvfpga.bit

地址编辑器

要执行的代码

#if defined(D_NEXYS_A7)
   #include <bsp_printf.h>
   #include <bsp_mem_map.h>
   #include <bsp_version.h>
#else
   PRE_COMPILED_MSG("no platform was defined")
#endif
#include <psp_api.h>


#define READ_IO(addr)  (volatile unsigned int *)(addr)
#define WRITE_IO(addr) (volatile unsigned int *)( addr)
#define inline_assembly()  asm("ori $0, $0, 0x1234")

#define UART_BASE 0x80111000


#define rbr 0*4
#define ier 1*4
#define fcr 2*4
#define lcr 3*4
#define mcr 4*4
#define lsr 5*4
#define msr 6*4
#define scr 7*4

#define thr rbr
#define iir fcr
#define dll rbr
#define dlm ier

void delay()
{
   for(unsigned int i=0;i<100000;++i);
}

int main()
{
    //printfNexys("hello world\n");
   *WRITE_IO(UART_BASE + lcr) = 0x00000080; // LCR[7]  is 1
   delay();
   *WRITE_IO(UART_BASE + dll) = 27;  // DLL msb. 115200 at 50MHz. Formula is Clk/16/baudrate. From axi_uart manual.
   delay();
   *WRITE_IO(UART_BASE + dlm) = 0x00000000;  // DLL lsb.
   delay();
   *WRITE_IO(UART_BASE + lcr) = 0x00000003;  // LCR register. 8n1 parity disabled
   delay();
   *WRITE_IO(UART_BASE + ier) = 0x00000000;  // IER register. disable interrupts
   delay();

   while (1) 
   {
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x00000048;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x00000065;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x0000006C;  
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x0000006C;  
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x0000006F;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x00000020;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x00000077;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x0000006F;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x00000072;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x0000006C; 
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x00000064;
      delay();
      *WRITE_IO(UART_BASE + thr) = 0x0000000A; 
      delay();              

   }
   return 0;
}

输出

目标：通过串口输出“Hello world”

我尝试通过更改UART_BASE的地址来使用其他比特流，它起作用了。所以问题可能出在UART_BASE的地址上，但我找不到任何文档来解决该问题。

Answer 1

下面这行应该注释掉，问题就解决了。

   // WRITE_IO((UART_BASE + dlm), 0x00000000);  // DLL lsb.