MC81F4x16
In mode 1, 10-bits are transmitted (through the TxD (R15) pin) or received (through the RxD (R14)
pin). Each data frame has three components:
-
-
-
Start bit ("0")
8 data bits (LSB first)
Stop bit ("1")
* The baud rate for mode 1 is variable depend on the BRDAT register value.
* Parity bit is not available for mode 1.( mode 2,3 provide parity bit )
Mode 1 Transmit Procedure
1. Set Rx pin to input mode and Tx pin to alternative mode.
2. Set the baud rate
- Select the UART clock by setting the UCLK(UCONL.[3-2]) bits.
- Set the BRDAT register properly
3. Select mode 1 by setting the USM(UCONH.[7-6]) bits.
4. Write transmission data to the UDAT.
After finish above steps, the data transmission will be started. And after the transmission is finished,
the UTIR(IRQL.3) bit is set to „1‟ by hardware.
Mode 1 Receive Procedure
1. Set Rx pin to input mode and Tx pin to alternative mode.
2. Set the baud rate
- Select the UART clock by setting the UCLK(UCONL.[3-2]) bits.
- Set the BRDAT register properly
3. Select mode 1 by setting the USM(UCONH.[7-6]) bits and set the SDR (UCONH.4 / Receive
Enable) bit in the UCONH register to "1".
After finish above steps, the receive operation starts when the signal at the RxD (R14) pin goes to low
level( start bit ). After the receiving is finished, the URIR(IRQL.4) is set to "1".
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October 19, 2009 Ver.1.35
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