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[SOLVED] Bug involving serial and C style character string


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Each AIS message dAISy received @9600 baud over the air, is output over serial in a single burst @38400 baud. If the MCU is still busy sending out a previous message over WiFi and/or another serial connection, while a new message is sent by dAISy, the receive buffer will overflow and the MCU misses the beginning of messages (as observed).

 

So the issue might have been more prelevant on the F5529 because a) the default length of the serial or WiFi/SPI output buffers are smaller on MSP430 than Tiva causing blocking writes, and/or B) SPI is clocked faster on Tiva making it faster pushing bytes to the CC3100, and/or c) the Tiva is simply faster in shuffling bytes.

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Each AIS message dAISy received @9600 baud over the air, is output over serial in a single burst @38400 baud. If the MCU is still busy sending out a previous message over WiFi and/or another serial connection, while a new message is sent by dAISy, the receive buffer will overflow and the MCU misses the beginning of messages (as observed).

 

So the issue might have been more prelevant on the F5529 because a) the default length of the serial or WiFi/SPI output buffers are smaller on MSP430 than Tiva causing blocking writes, and/or B) SPI is clocked faster on Tiva making it faster pushing bytes to the CC3100, and/or c) the Tiva is simply faster in shuffling bytes.

Ah k, gotcha.  SPI isn't clocked faster on the Tiva (defaults to 4MHz but adjustable) although I always recommend raising the SPI speed for any serious CC3100 use, but the UART ring buffer size is the most significant factor here, since the Tiva's default is 256 bytes and MSP430 is hardcoded to 16.

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