In document《SPNU499RM48 16/32-Bit RISC Flash Microcontroller Technical Reference Manual》 page1450 note that it need I/O port software method to monitor USART , but in document 《Configuring the Hercules™ ARM® Safety MCU SCI/LIN Module for UART Communication》which provide the configuration procedure, but it do not need the software I/O monitor. Why? note ：SCI module does not support UART Hardware Flow Control. This feature can be implemented in Software using a General Purpose I/O pin SPNU499 page1423 tell that serial port speed testing, what is the meaning of "PercentError -0.15", why it is negative?
Hello Hanson,
I have asked one of our SCI experts to get back with you.
Hi Hanson,
SCI available in the RM48x devices has only TX & RX pin and no CLK pin or other Handshaking ( flow control signals). Hence using this module to talk to any Syncronous system need an I/O pin which has to be controlled in the software to act like Clock pin.
The configuration procedure mentioned in the document was for an Asyncronous communication which does not mandate Clcok pin. This is typically used to talk to the PC ( RS232).
SInce there is no Handshaking pins ( Flow control pins like RTS / CTS) available in the module, hence inorder to use Handshaking user has to do it through General purpose I/O pin & software.
"PercentError -0.15" becasue the Actual value is less thatn the ideal value, But this is considering only a particular VCLK frequency 50MHz.
-Prathap
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