STM32F4 Discovery and printf() redirection to debug viewer in Keil MDK-ARM
使用Keil开发STM32F4 Discovery板的时候，使用printf函数，并且，输出信息重定向到debuger中的debug viewer中，从而，增加调试手段。
http://armcortexm.blogs.upv.es/stm32f4-discovery-and-printf-redirection-to-debug-viewer-in-keil/
Objective
The ARM Cortex-M architecture includes a facility for sending/receiving user data through special debug ports. This facility is well suited for typical printf() debug practices, where a typical serial port is utiliced. In theses cases, the idea is to write in my program something like this,
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#include <stdio.h>
void
main (
void
) {
printf
(
"Hello, world!"
);
}
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and use the “Debug (printf) viewer” option avaible in Keil MDK-ARM (and other environments) to show a terminal where messages are received. See bellow
These are my notes in order to get this mechanism working on the STM32F4 Discovery kit using the Keil environment.
Some vocabulary.
ITM:
SWV: Serial Wire Viewer
St-Link/V2 upgrade and drivers
The STM32F4 Discovery includes a built-in St-link/v2 debug interface. According with its manual, the SWV facility is available in this interface and the hardware lines are propagated in the schematic of the Discovery kit.
Steps:
1 – Download drivers and utilities from the support page for St-Link/v2 for Windows Xp and 7
2 – Install drivers (?Uninstall previous driver from the control panel)
3- Upgrade St-Link/v2 interface of the discovery running the ST-LinkUpgrade.exe utility
Configuring a Keil project
(But not working completly OK)
Assuming you have a working example for the previous debugger version. (Try to) follow these steps:
1 – Open your project and open the “target options” dialog
2 – Select the second “St-link debugger”
3 – Select “settings” and set options according to the next images.
(Here, be carefull with the speed of the core).
(This a trick for flashing the microcontroller)
Redirecting/retargeting printf() in my program
Create a C module that includes the following code and add it to your project
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/**
@file fputc_debug.c
@brief Trying to redirect printf() to debug port
@date 2012/06/25
*/
#include <stdio.h>
#include <stm32f4xx.h>
int
fputc
(
int
c,
FILE
*stream)
{
return
(ITM_SendChar(c));
}
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And start playing!
To be solved!!!!
The problem now is that the code is not flashed when entering in debug mode. I follow these steps:
1 – Rebuild completly the project (to avoid that the systems assumes that the build has been done)
2 – Flash the microcontroller with the “load” button
3 – Start debugging