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STM32F2 Smartcard mode with DMA

Question asked by wong.wai_hong on Feb 5, 2014
Hi Support,

As to date, I have successfully implement smart card TX and RX together with DMA. But I encounter a problem. It is regarding on guard time. As per Reference Manual, the guard time can be configured, but it will only delay and affecting the TC interrupt. But as in USART DMA, the TC interrupt will only happened after all the data is transmitted.

As per ISO7816-3 standard, the guard time is defined as the stop bit of each character, meaning that every characters must have the predefined guard time.

Is there anyway I can solve this with DMA?? FYI, I also tried to use TC interrupt approach. From what I probed from Logic Analyser, it seems that there's additional (unwanted) 1 stop bit. Hope you guys help.