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?