IBM EM78P312N manual UART Universal Asynchronous Receiver/Transmitter, Bit Microcontroller

EM78P312N

8-Bit Microcontroller

5.7 UART (Universal Asynchronous Receiver/Transmitter)

Registers for UART Circuit

R_BANK	Address	Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
Bank 2	0X05	URC1	URTD8	UMODE1	UMODE0	BRATE2	BRATE1	BRATE0	UTBE	TXE
			R/W	R/W	R/W	R/W	R/W	R/W	R	R/W
Bank 2	0X06	URC2	0	0	SBIM1	SBIM0	UINVEN	0	0	0
			--	--	R/W	R/W	R/W	--	--	--
Bank 2	0X07	URS	URRD8	EVEN	PRE	PRERR	OVERR	FMERR	URBF	RXE
			R/W	R/W	R/W	R/W	R/W	R/W	R	R/W
Bank 2	0X08	URRD	URRD7	URRD6	URRD5	URRD4	URRD3	URRD2	URRD1	URRD0
			R	R	R	R	R	R	R	R
Bank 2	0X09	URTD	URTD 7	URTD 6	URTD 5	URTD 4	URTD 3	URTD 2	URTD 1	URTD0
			W	W	W	W	W	W	W	W
Bank 0	0x0F	ISFR2	0	UERRIF	RBFF	TBEF	TBIF	EXIF1	0	TCIF0
			--	R/W	R/W	R/W	R/W	R/W	--	R/W
SFR	0x0F	IMR2	0	UERRIE	URIE	UTIE	TBIE	EXIE1	0	TCIE0
			--	R/W	R/W	R/W	R/W	R/W	--	R/W

	TC4
	Fsystem	Selector	Baud rate
			generator
	RXE	RX Control		Interrupt	TX Control		TXE
				Control
RX
	RX shift register			Parity control			TX
UINVEN	URRD8	URRD		Error flag	URTD8	URTD
				Data Bus			UINVEN

Fig. 5-10 Function Block Diagram

In Universal Asynchronous Receiver Transmitter (UART), each transmitted or received character is individually synchronized by framing it with a start bit and stop bit.

Full duplex data transfer is possible since the UART has independent transmit and receive sections. Double buffering for both sections allows the UART to be programmed for continuous data transfer.

28 • Product Specification (V1.0) 10.03.2006

(This specification is subject to change without further notice)