Hi,
I am using the STM32F437 USART with Keil PPP and a 2G/4G modem.
Keil's PPP client uses Keil's CMSIS USART driver.
The STM32F437 USART has an automatic flow control feature. CTS and
RTS will be handled automatically by the MCU. However, the MCU only
has a 1 byte internal buffer which means that RTS is
asserted/de-asserted on every received character.
This limitation means that if my MCU is communicating with the modem
at a high baud rate of 2040800 then the RTS signal will b
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