Such transmission takes time being one bit at a time during which time the

Such transmission takes time being one bit at a time

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Such transmission takes time (being one bit at a time), during which time the program should not modify T. Thus, before writing to T, the program must ensure the UART is ready for transmitting by checking that a global flag variable, TxReady, is 1. TxReady is automatically set to 0 by the UART hardware while busy transmitting, and to 1 when done transmitting. For receiving, instead of showing the rx pin, RIMS has a "UART input" text box in which a user may type characters, whose 8 bits (per ASCII) are received serially into a special global variable R. o The UART informs the program when new data has been received into R by automatically calling an ISR function " void RxISR() " that the programmer must define. Our convention is to have that ISR set a flag that the program may then read to determine that new data was received by the UART. The UART hardware automatically detects when R is read by the program, after which the UART hardware may overwrite R when new data is received. o Until R is read by the program, the UART hardware will not overwrite R. A common error is to forget to turn on the UART Another common error is to fail to read R when data is there, thus preventing the hardware from calling the RxISR function. 7.3 Analog-Digital conversion An analog-to-digital converter or ADC (sometimes A2D ) converts an analog signal into a digital signal, which a microcontroller program can then use.
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