MC81F4x16
Mode 2 / 3 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( in mode 3 only )
3. Select mode 2 or 3 by setting the USM(UCONH.[7-6]) bits.
4. Set the 9th bit, there are two way to set the 9th bit.
- Set the „UTP(UCONL.7 / parity auto-generatio)‟ bit by „1‟
- Or, Clear „UTP(UCONL.7 / parity auto-generation)‟ bit by „0‟
and write the 9th bit data to the TB8(UCONH.3) bit as you want.
5. Write transmission data to the UDAT.
After finish above steps, the data transmission will be started. And after finish the transmission, the
UTIR(IRQL.3) bit is set to „1‟ by hardware.
Mode 2 / 3 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( in mode 3 only )
3. Select mode 2 or 3 by setting the USM(UCONH.[7-6]) bits.
4. If you want, set the MCE(UCONH.5 / multi-processor communication enable) bit
If you do not want the MCE feature, do not have to set the MCE bit.
5. Set the SDR(UCONH.4 / receive enable) bit by „1‟.
6.
After finish above steps, the receive operation starts when the signal at the RxD (R14) pin goes to low
level( start bit ). After finish receiving, the URIR(IRQL.4) is set to "1".
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October 19, 2009 Ver.1.35
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