W925EP01 Datasheet, PDF (58/108 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925EP01/ W925EP01FG
MODE 3
This mode is similar to Mode 2 in all respects, except that the baud rate is programmable. The user
must first initialize the Serial related SFR SCON before any communication can take place. This
involves selection of the Mode and baud rate. The Timer 0 or 1 or baud rate generator (BG) should
also be initialized if modes 1 and 3 are used. In all four modes, transmission is started by any
instruction that uses SBUF as a destination register. Reception is initiated in Mode 0 by the condition
RI = 0 and REN = 1. This will generate a clock on the TxD pin and shift in 8 bits on the RxD pin.
Reception is initiated in the other modes by the incoming start bit if REN = 1. The external device will
start the communication by transmitting the start bit.
SM1
0
0
1
1
SM0
0
1
0
1
MODE
0
1
2
3
Table 10 Serial Ports Modes
TYPE
BAUD CLOCK
FRAME
SIZE
Synch. 4 or 12 TCLKS 8 bits
Asynch.
Timer 0 or 1
10 bits
Asynch. 16 or 32 TCLKS 11 bits
Asynch.
Timer 0 or 1
11 bits
START
BIT
No
1
1
1
STOP
BIT
No
1
1
1
9TH BIT
FUNCTION
None
None
0, 1
0, 1
Fosc
BGEN= BGCON.0
BG_Counter
BG
Figure 6-11 Serial Port0 Baud Rate Generator Mode
BG_counter
overflow
- 58 -