Serial port RX problem with IAR compiler

[mstevanovic]

I am using ST Nucleo F103RB platfrom with IAR compiler 7.20.
printf to serial port is OK. But, if I want to read from serial port this is not possible.
I am using Serial_HelloWorld_Mbed example and function is blocked on getc

There is no problem with ARM or GCC compiler. Only with IAR...

Best regards
Milan

[GustavWi]

Can you post the exact program you are using? @mstevanovic
//Gustav

[mstevanovic]

Hi,

I am using example from mbed. Serial_HelloWorld_Mbed...
This is a link:
https://developer.mbed.org/handbook/Serial

Code:
#include "mbed.h"

Serial pc(USBTX, USBRX); // tx, rx

int main() {
pc.printf("Hello World!\n");
while(1) {
pc.putc(pc.getc() + 1);
}
}

Also, I noticed that mbed test faild for IAR compiler (serial echo test...):
+---------+---------------+-----------+-----------+---------------------------------------+--------------------+---------------+-------+
| Result | Target | Toolchain | Test ID | Test Description | Elapsed Time (sec) | Timeout (sec) | Loops |
+---------+---------------+-----------+-----------+---------------------------------------+--------------------+---------------+-------+
| FAIL | NUCLEO_F103RB | IAR | MBED_24 | Timeout Int us | 25.8 | 15 | 0/1 |
| TIMEOUT | NUCLEO_F103RB | IAR | MBED_A9 | Serial Echo at 115200 | 20.77 | 10 | 0/1 |
| OK | NUCLEO_F103RB | IAR | MBED_23 | Ticker Int us | 14.34 | 15 | 1/1 |
| OK | NUCLEO_F103RB | IAR | MBED_25 | Time us | 14.39 | 15 | 1/1 |
| OK | NUCLEO_F103RB | IAR | MBED_26 | Integer constant division | 4.44 | 10 | 1/1 |
| OK | NUCLEO_F103RB | IAR | MBED_34 | Ticker Two callbacks | 14.45 | 15 | 1/1 |
| OK | NUCLEO_F103RB | IAR | DTCT_1 | Simple detect test | 3.51 | 10 | 1/1 |
| FAIL | NUCLEO_F103RB | IAR | EXAMPLE_1 | /dev/null | 8.75 | 10 | 0/1 |
| OK | NUCLEO_F103RB | IAR | MBED_A1 | Basic | 4.29 | 10 | 1/1 |
| OK | NUCLEO_F103RB | IAR | MBED_A21 | Call function before main (mbed_main) | 4.39 | 10 | 1/1 |
| OK | NUCLEO_F103RB | IAR | MBED_10 | Hello World | 3.38 | 10 | 1/1 |
| OK | NUCLEO_F103RB | IAR | MBED_11 | Ticker Int | 14.44 | 20 | 1/1 |
| OK | NUCLEO_F103RB | IAR | MBED_12 | C++ | 4.43 | 10 | 1/1 |
| FAIL | NUCLEO_F103RB | IAR | MBED_16 | RTC | 13.48 | 15 | 0/1 |
| FAIL | NUCLEO_F103RB | IAR | MBED_2 | stdio | 13.49 | 20 | 0/1 |
+---------+---------------+-----------+-----------+---------------------------------------+--------------------+---------------+-------+

[mstevanovic]

Also, I noticed, from retarget.cpp next function is called
extern "C" size_t __read (int fh, unsigned char *buffer, size_t length)

and length parameter is 512... but from main, getc is called...

regards
Milan

[GustavWi]

Yes regarding serial echo test. gets(buffer, buffer size) call never returns. __read that is overwritten never returns -1 because it reads a unsigned char. fgets (a dlib function for IAR) allocates pages of 512 bytes to store the stream. When it encounter EOF it stops and fills the input buffer with as much of the pages as it can contain. The problem is that __read never encounter EOF and therefore just more pages get filled.

[mstevanovic]

OK. but in this example getc is called and in __read I see that length is 512... Why?
for gets and getc 512 bytes are allocated?

[mstevanovic]

Hi Gustav,

I see some fix for on github for this problem. I take example and export to IAR and still have same problem. I am using next mbed revision: 92:4FC01DAAE5A5
This is from mbed online compiler and I did export to IAR. IAR compiler 7.20 is used.

[0xc0170]

@mstevanovic Did you use mbed-src (replace mbed lib with mbed-src)? I believe the revision is for the mbed library.

[mstevanovic]

OK. I will try with mbed-src. My fault, I used mbed lib.
Thanks....

[mstevanovic]

Yes. It is OK. Thanks a lot.

[GustavWi]

Glad to hear that. Good luck!