Signal DescriptionMCF5253 Reference Manual, Rev. 12-8 Freescale Semiconductor2.9 Serial Module SignalsThe following signals transfer serial data between the three UART modules and external peripherals.2.10 Timer Module SignalsThe following signal provides an external interface to Timer0. One 16-bit timers can trigger externalevents or both 16-bit timers can trigger internal interrupts.2.11 Serial Audio Interface SignalsThe following signals provide the external audio interface.Table 2-3. I 2 C Module SignalsI 2 c Module Signal DescriptionI 2 C Serial Clock The SCL0/SDATA1_BS1/GPIO41, and SCL1/TXD1/GPIO10 bidirectional signals are the clock signal forfirst and second I2 C module operation. The I 2C module controls this signal when the bus is in master mode;all I 2C devices drive this signal to synchronize I2 C timing.Signals are multiplexed.I 2C Serial Data The SDA0/SDATA3/GPIO42 and SDA1/RXD1/GPIO44 bidirectional signals are the data input/output forthe first and second serial I 2 C interface.Signals are multiplexed.Table 2-4. Serial Module SignalsSerial Module Signal DescriptionReceive Data The RXD0/GPIO46, SDA1/RXD1/GPIO44, and EF/RXD2/GPIO6 are the inputs on which serial data isreceived by the UART. Data is sampled on RxD[2:0] on the rising edge of the serial clock source, withthe least significant bit received first.Transmit Data The UART transmits serial data on the TXD0/GPIO45, SCL1/TXD1/GPIO10, and XTRIM/TXD2/GPIO0output signals. Data is transmitted on the falling edge of the serial clock source, with the least significantbit transmitted (LSB) first. When no data is being transmitted or the transmitter is disabled, these twosignals are held high. TxD[2:0] are also held high in local loopback mode.Request To Send The DDATA3/RTS0/GPOI4 and DDATA1/RTS1/SDATA2_BS2/GPIO2 request-to-send outputs indicateto the peripheral device that UART0/1 are ready to send data and requires a clear-to-send signal toinitiate transfer. The third UART lacks flow control using RTS/CTS.Clear To Send Peripherals drive the DDATA2/CTS0/GPIO3 and DDATA0/CTS1/SDATA0_SDIO1/GPIO1 inputs toindicate to the MCF5253 serial module that it can begin data transmission. The third UART lacks flowcontrol using RTS/CTS.Table 2-5. Timer Module SignalsTimer Signal DescriptionTimer Output The SDATAO1/TOUT0/GPIO18 programmable output pulse or toggle on various timer events.
