Fix IRQ enabled in serial_irq_set()

[arnaudrichard]

This is resolution of #1586
UART_IT_TC was enabled instead of UART_IT_TXE
This was causing an issue because UART_IT_TXE (and not UART_IT_TC) was disabled by same function.
Consequently if a transfer was ongoing when serial_irq_set() was called to disable IRQ, UART_IT_TC would still trigger (once).
Side effect is maybe speed: I guess using UART_IT_TC prevented implementation of continuous transfer.
This commit is focused on solving an issue observed with TARGET_STM32F4. It doesn't presume it should or shouldn't be done for other targets.

[0xc0170]

@bcostm @adustm

[0xc0170]

@arnaudrichard Please sign https://developer.mbed.org/contributor_agreement/

[arnaudrichard]

Done.

From: Martin Kojtal [mailto:notifications@github.com]
Sent: jeudi 10 mars 2016 16:15
To: mbedmicro/mbed
Cc: Arnaud RICHARD
Subject: Re: [mbed] Fix IRQ enabled in serial_irq_set() (#1603)

@arnaudrichardhttps://github.com/arnaudrichard Please sign https://developer.mbed.org/contributor_agreement/

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[0xc0170]

What about the line 95, does your patch affects that line:

__HAL_UART_DISABLE_IT(handle, UART_IT_TC|UART_IT_TXE);

cc @bcostm

[arnaudrichard]

__HAL_UART_DISABLE_IT(handle, UART_IT_TC|UART_IT_TXE);
looks good to me and should not be affected by my patch.

cc @bcostmhttps://github.com/bcostm

From: Martin Kojtal [mailto:notifications@github.com]
Sent: lundi 14 mars 2016 17:24
To: mbedmicro/mbed
Cc: Arnaud RICHARD
Subject: Re: [mbed] Fix IRQ enabled in serial_irq_set() (#1603)

What about the line 95, does your patch affects that line:

__HAL_UART_DISABLE_IT(handle, UART_IT_TC|UART_IT_TXE);

cc @bcostmhttps://github.com/bcostm

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Reply to this email directly or view it on GitHubhttps://github.com//pull/1603#issuecomment-196395845.