IBM EM78P312N manual Uart Mode, Transmitting

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EM78P312N

8-Bit Microcontroller

The figure below shows the general format of one character sent or received. The communication channel is normally held in the marked state (high). Character transmission or reception starts with a transition to the space state (low).

The first bit transmitted or received is the start bit (low). It is followed by the data bits, in which the least significant bit (LSB) comes first. The data bits are followed by the parity bit. If present, then the stop bit or bits (high) confirm the end of the frame.

In receiving, the UART synchronizes on the falling edge of the start bit. When two or three “0” are detected during three samples, it is recognized as normal start bit and the receiving operation is started.

							Idle state
START	D0	D1	D2	Dn	Parity	STOP	(mark)
bit	D0	D1	D2	Dn	bit	bit
bit					bit	bit
1 bit			7 or 8 bits		1 bit	1 bits
			One character or frame
							I

Fig. 5-11 Data Format in UART

5.7.1 UART Mode

There are three UART modes. Mode 1 (7 bits data) and Mode 2 (8 bits data) allow the addition of a parity bit. The parity bit addition is not available in Mode 3. The Figure below shows the data format in each mode.

	UMODE		PRE	1	2	3	4	5	6	7	8	9	10	11
Mode 1	0	0	0	START			7 bits DATA					STOP
Mode 1
	0	0	1	START			7 bits DATA					Parity	STOP
Mode 2	0	1	0	START			8 bits DATA						STOP
Mode 2
	0	1	1	START			8 bits DATA						Parity	STOP
Mode 3	1	0	X	START			9 bits DATA							STOP

Fig. 5-12 UART Mode

5.7.2 Transmitting

In transmitting serial data, the UART operates as follows:

1.Set the TXE bit of the URC1 register to enable the UART transmission function.

2.Write data into the URTD register and the UTBE bit of the URC1 register will be set by hardware.

Product Specification (V1.0) 10.03.2006

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(This specification is subject to change without further notice)

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Contents DOC. Version EM78P312NElan Microelectronics Corporation Contents 16.1 14.116.2 16.3Bit Microcontroller General DescriptionPin Description Symbol Pin No Type FunctionFunction Description Functional Block DiagramOperating Registers Operating RegistersBit Microcontroller R0 Indirect Addressing Register R1 Time Clock /CounterR2 Program Counter & Stack R3 Status Register User Memory SpaceBit 7 ~ Bit 6 RBS1 ~ RBS0 R-Register page select RBS1 RBS0SIS = 0 Idle mode SIS = 1 Sleep mode Bit 1 SIS Sleep and Idle mode selectBit 0 C Carry flag R4 RAM Select Register R5 System Control RegisterBit Microcontroller R6 Port 6 I/O Data Register RB Timer/Counter 4 Control RegisterBit 7 ~ Bit 0 P67 ~ P60 8-bit Port 6 I/O data register R7 Port 7 I/O Data RegisterClock Source Resolution Max. Time RC Timer 4 Data BufferTC4CK2 TC4CK1 TC4CK0 Fosc=8MRFInterrupt Status Flag Register Bit Microcontroller RE Interrupt Status Flag RegisterTC3M = 1 Capture mode Bank 1 R6 TC3DA Timer 3 Data Buffer a Bank 1 R5 TC3CR Timer/Counter 3 Control RegisterBank 1 R7 TC3DB Timer 3 Data Buffer B Bit 7 TC3CAP Software capture controlBank 1 RA TC2DL Timer 2 Data Buffer Low Byte Bank 1 R9 TC2DH Timer 2 Data Buffer High ByteTC2S = 0 Stop and counter clear Bank 1 RB Adcr AD Control RegisterBit 5~ Bit 4 ADCK1 ~ ADCK0 AD Conversion Time Select Bit 7 ~ Bit 0 ADE7 ~ ADE0 AD input pin enable controlBank 1 RC Adic AD Input Pin Control Bank 1 RD Addh AD High 8-bit Data BufferBit Microcontroller Bank 1 RE Tbktc TBT/Keytone Control TEN = 0 Disable TEN = 1 EnableBank 2 R5 URC1 Uart Control Register BitBit 7 URRD8 Receiving data Bit Bank 2 R7 URS Uart Status RegisterBRATE2 BRATE1 BRATE0 TC2CK1 TC2CK0Bit 6 Even Select parity check Bit 5 PRE Enable parity additionEven = 0 Odd parity Even = 1 Even parity Bank 2 R9 Urtd Uart Transmit Data BufferBit 2 EDS Data shift out edge select Bit 5 ~ Bit 3 BRS0 ~ BRS2 SPI Clock Source SelectEDS = 0 Rising edge EDS = 1 Falling edge Bit 0 WBE Write buffer empty flag. Read onlyTransfer Mode PHE6x = 1 Disable P6x pull highBank 3 RB PLC1 Pull Low Control Register SPID7 SPID6 SPID5 SPID4 SPID3 SPID2 SPID1 SPID0Special Purpose Registers Intcr − INT Control Register Address 0Bh IOC6 ~ IOC9 − I/O Port Control RegisterINT1ES = 0 Rising edge INT1ES = 1 Falling edge TC2ES = 0 Rising edge TC2ES = 1 Falling edgeExternal Interrupt Adoscr − AD Offset Control Register Address 0ChCali Sign Uerrie Urie Utie Tbie EXIE1 TCIE0 IMR2 − Interrupt Mask Register 2 Address 0FhRegisters for CPU Operation Mode CPU Operation ModeMode Switching Control Operation ModeWake-up Signal R5 SIS = 1+SLEP R5 SIS= 0 + Slep Instruction Sleep Mode Idle ModeAD Converter Wake-up MethodsADC Data Register Operation Mode Max. Frequency Max. Conversion Rate per BitSampling Time Conversion TimeAddress Name Bit Time Base Timer and Keytone GeneratorMUX Uart Universal Asynchronous Receiver/Transmitter Registers for Uart CircuitName Bit Transmitting Uart ModeBaud Rate Generator ReceivingSPI Serial Peripheral Interface Registers for the SPI CircuitRbank Address Name Bit Transfer Mode Shift Direction and Sample PhaseBit Transmit Mode Serial ClockBit Microcontroller Bit Receive Mode Bit Transmit/Receive ModeSCK pin Multiple Device Connect /SS SpisRegisters for Timer/Counter 2 Circuit Timer/CounterTimer Mode Counter ModeWindow Mode 21 Window Mode Timing Chart Registers for Timer/Counter 3 Circuit22 Configuration of Timer/Counter3 Capture ModeTCIF4 Registers for Timer 4 CircuitTCR4 PDO Mode12 TCC/WDT & Prescaler PWM ModeUp-counter TC4 InterruptReset and Wake-up Reset13 I/O Ports Wake-up from Idle Mode Wake-up from Sleep ModeSummary of the Initialized Values for Registers Address Name Reset Type BitSCR Bit Microcontroller Register BankAddres URTD8 Status of RST, T, and P of the Status Register Reset TypeBit Microcontroller General Purpose Registers Events that may affect the T and P StatusInterrupt 28 Controller Reset Block DiagramOscillator Modes OscillatorCrystal Oscillator/Ceramic Resonators Crystal Summary of Maximum Operating Speeds740 EM78P312N 809N Oscillator Type Frequency Mode Frequency C1 pF C2 pFOS CI External RC Oscillator ModeCode Option Register Enwdtb = 0 Enable Enwdtb = 1 DisableCode Option Register Word Bit 12 ~ 9 Not usedExternal Power-on Reset Circuit Power-on ConsiderationsCustomer ID Register OSC = 0 RC type OSC = 1 Crystal typeVdd Residue-Voltage ProtectionEM78P312N EM78P809NBinary Instruction Hex Mnemonic Operation Status Instruction SetDEC Binary Instruction Hex Mnemonic Operation Status AffectedAbsolute Maximum Ratings Symbol Parameter Condition Min Typ Max UnitRecommended Operating Conditions Vss =Ta= 25 C, VDD= 5.0V ± 5%, VSS= DC Electrical CharacteristicsTa= 25 C, VDD= 3.0V ± 5%, VSS= Varef AC Electrical Characteristic Symbol Parameter Conditions Min Typ Max UnitTa=- 40C ~ 85 C, VDD=5V ± 5%, VSS=0V AC Test Input/Output Waveform Timing DiagramPackage Type OTP MCUPin Count Package Size EM78P311SxY