5 SCI 异步串行通讯l

Asynchronies Serial Communication
RS-232C Only for ASCII 3 wires connection: (25 pins D type Connector)
DTE / DCE 2 TxD 3 RxD 7 GND 4 RTS 5 CTS 6 DSR 8 DCD 20 DTR out in out in in in out TxD RxD GND RTS CTS DSR DCD DTR
OUTCH CHKSTS
Transmit
Routine OUTCH send an ASCII in B to SCI0 No
Read Status
If Empty? Yes
ORG BRCLR STAB RTS
$2000
Send [B]
OUTCH
SCI0SR1,#$80,* SCI0DRL ;Write Transmit Data to
Asynchronies Serial Communication
RS-232C
DTE ( 9 pins connector) in PC 1 protection ground 2 RxD in 3 TxD out 5 6 7 8 9 4 GND DSR RTS CTS DCD DTR
RxD (Receive Data) TxD (Transmit Data ) GND DSR RTS CTS DCD DTR
(9 pins D type Connectors)
TxD RxD GND RTS CTS DSR DCD DTR Transmit Data Receive Data Require To Send Clear To Send Data Set Ready Data Care Detected Data Terminal Ready
SCTIE=0 TCIE =0 SCRIE=0 IDLE =0 TE = 0 RE = 0 RWU =0 SBK = 0
Enable SCI0 T & R
LDAA # %00001100 ; Initial SCI STAA SCI0CR2 ; Enable T & R
OR you can use: BSET SCI0CR2, # %00001100 ;Enable T&R
Diff. Form MCU to MCU
SCI Control Register 1 : SCCR1
$CA LOOPS SCISWAI RSRC
Reset
0
0
0
M WAREILT 0 0 0
PE 0
PT 0
LOOPS=0 SCISWAI=0 RSRC =0 M=0 WARE=0 ILT =0 PE = 0 PT = 0
Nice to Use Default !
SCI Control Register 2 : SCCR2
B7
$CB SCTIE
6
5
4
3
2
1
0
TCIE SCRIE IDLE TE RE RWU SBK Transmit Buffer Empty IRQ Disabled Transmit Complete IRQ Disabled Receiver Buffer Full IRQ Disabled Idle Line IRQ Disabled Transmit Disabled Receive Disabled Receiver Is Not in Receiver Wake Up Mode Transmit Break Bit, Not Break.
(Transmit Data ) (Receive Data) (Ground) (Require to Send) (Clear to Send) (Data Terminal Ready) (Data Carry Detected) (Data Set Ready)
Ready always, or XON/XOFF protocol, ASCII only!
STAA SCI0BDL CLR SCI0CR1
Transmit & Receive with SCI
SCI States Register ($CD)
B7 $CD TDRE 6 TC 5 RDRF 4 IDLE 3 OR 2 NF 1 FE 0 PE
TDRE=1, TC RDRF=1, IDLE OR NF FE PE
(Ground) (Data Terminal Ready) (Require to Send) (Clear to Send)
in out in in out
(Data Carrier Detected)
(Data Set Ready)
No Handshake, should use XON/XOFF protocol,ASCII only
Use Macro in C : #define get_char() {_asm BRCLR $CC,#$80,*; _asm STAB $CF ; }
OUTCH
ORG LDA BITA BEQ STAB RTS $2000 #$80 SCI0SR1 CHKSTS SCI0DRL ; TDRE is at bit7 ; SCI0 Status Register ; If bit clear, check again ; Write Transmit Data to
Do Not in Self Loop Mode SCI not stopped in wait mode Receiver Source not from LOOP mode 8 Bits, not 9 Bits Wake up Mode IS Idle, Not Address Idle Counter form Start Bits No Parity If Parity, Use Even
SCI
Synchronize Communication Interface
RS-232 in S12
Asynchronies Serial Communication SCI
BUAD RATE: 1 Bit / Sec = 1 Buad (Bit Per Second, BPS) standard rate(very wide bound wades ):
SCI Based Other Communication Protocol
Modem 20 mA current loop RS-485 Local Intercommunication Network (LIN) Similar method to access other Modules like LIN, SPI, CAN, J1850, Ethernet……
Asynchronies Serial Communication
and RS-232C Signals Voltage Levers
1= -3V ~ - 15V 0 = +3V ~ + 15V (150 feet)
Signals definitions
– DTE 3 2 5 7 8 6 9 4 / DCE TxD RxD GND RTS CTS DSR DCD DTR out in out in in in out
Asynchronies Serial Communication
Use Not Return to Zero (NRZ) code T & R is synchronized by start bit detection R Clock = T Clock x 16 (baud rate x 16), slow 3,5,7 clock detect fowling edge of start bit 8,9,10 detect bit's value (Anti-Noise ) The maximum speed: bus rate /16 Duplex and Half Duplex
Discussion: 0 Not Valid! Maximum baud Rate = ?
SCI Initialization
Already did in the debug SCI0INIT LDAA #0C STAA SCI0CR2 LDAA #$9C ; Initial SCI ; Enable T & R ; Set Baud Rate to 9600 ; $4E for 19200... ; 8bit, No Parity…..Not necessary
S12 SCI Module Registers
SCI0BDH SCI0BDL SCI0CR1 SCI0CR2 SCI0SR1 SCI0SR2 SCI0DRH SCI0DRL EQU EQU EQU EQU EQU EQU EQU EQU $C8 $C9 $CA $CB $CC $CD $CE $CF ;Baud Rate Register High ; Low ;Control Register1 ;SCI Control Register 2 ;Status Register 1 ;Status Register 2(SCISR2 ;Data Register High ;SCI Data Register Low
OUTCH CHKSTS
Or: BRCLR STAB RTS SCI0SR1,#$80,* SCI0DRL ;Write Transmit in C
#define SCI0SR1 0xcc; #define SCI0DRL 0xcf; Put_Char(char a) { while ((*SCI0SR1 & 0x80) == 0); *SCI0DRL = c; }
Try if it works