VRS51L1050
Timer 1 Reload Value in Modes 1 and 3 for UART Baud Rate
The following table provides examples of the Timer 1, 8-bit reload value when it is used as a UART baud rate
generator and the SMOD bit of the PCON register is set to 1.
22.184MHz
16.000MHz
14.745MHz
12.000MHz
11.059MHz
8.000MHz
3.57MHz
115200bps
57600bps
38400bps
31250bps
19200bps
9600bps
2400bps
1200bps
300bps
FFh
Feh
FDh
-
FAh
F4h
D0h
A0h
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
FFh
-
-
FDh
FAh
E8h
D0h
40h
FEh
-
FEh
-
-
E6h
CCh
30h
FCh
F8h
E0h
C0h
00h
DDh
BBh
-
DDh
75h
C2h
Timer 2 Reload Value in Modes 1 and 3 for UART Baud Rate
The following are examples of [RCAP2H, RCAP2L] reload values for Timer 2 when it is used as baud rate generator
for the VRS51L1050 UART.
22.184MHz
FFFDh
FFFAh
FFF4h
FFEEh
FFEAh
FFDCh
FFB8h
FEE0h
FDC0h
F700h
16.000MHz
-
14.745MHz
FFFEh
FFFCh
FFF8h
FFF4h
FFF1h
FFE8h
FFD0h
FF40h
FE80h
FA00h
12.000MHz
11.059MHz
-
8.000MHz
3.57MHz
230400bps
115200bps
57600bps
38400bps
31250bps
19200bps
9600bps
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
FFFDh
FFFAh
FFF7h
FFF5h
FFEEh
FFDCh
FF70h
FEE0h
FB80h
FFF3h
FFF0h
FFE6h
FFCCh
FF30h
FE5Fh
F97Dh
FFF4h
-
FFD9h
FF64h
FEC7h
FB1Eh
FFF8h
FFF3h
FFE6h
FF98h
FF30h
FCBEh
-
2400bps
1200bps
300bps
FFD1h
FFA3h
FE8Bh
UART Initialization in Mode 3 Using Timer 1
UART Initialization in Mode 3, Using Timer 2
;*** INTIALIZE THE UART @ 9600BPS, Fosc=11.0592MHz
;*** INTIALIZE THE UART @57600BPS, Fosc=11.0592MHz
INISER0T1I: MOV A,T2CON
ANL A,#11001111B
MOV T2CON,A
;RETRIEVE CURRENT VALUE OF T2CON
;RCLK & TCLK BIT = 0 -> TO USE TIMER1
;BAUD RATE GENERATOR SOURCE FOR UART
;SET THE SMOD BIT TO 1
;CONFIG TIMER1 AT 8BIT WITH AUTO-RELOAD
;CALCULATE THE TIMER 1 RELOAD VALUE
;TH1 = [(2^SMOD) * Fosc] / (32 * 12 * Fcomm)
;TH1 FOR 9600BPS @ 11.059MHz = FAh
;CONFIG SCON_0 MODE_1
INISER0T2I: MOV SCON,#05Ah
;CONFIG SCON_0 MODE_1,
;CALCULATE RELOAD VALUE WITH T2
;RCAP2H,RCAP2L = 65536 - [ Fosc / (32*Fcomm)]
MOV PCON,#80H
MOV TL1,#0FAH
MOV TH1,#0FAH
MOV RCAP2H,#0FFh ;RELOAD VALUE 57600bps, 11.059MHz =FFFAh
MOV RCAP2L,#0DCh
;
MOV T2CON,#034h
;SERIAL PORT0, TIMER2 RELOAD START
MOV SCON,#05Ah
MOV TMOD,#00100000B ;CONFIG TIMER 1 IN MODE 2, 8BIT
; + AUTO RELOAD
MOV TCON,#01000000B ;START TIMER1
CLR SCON.0
CLR SCON.1
;CLEAR UART RX, TX FLAGS
CLR SCON.0
CLR SCON.1
;CLEAR UART RX, TX FLAGS
MOV SBUF,#DATA
;SEND ONE BYTE ON THE SERIAL PORT
MOV SBUF,#DATA
;SEND ONE BYTE ON THE SERIAL PORT
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