Panasonic MN101C00 Cell Phone User Manual


 
5-3-3 How to Use the Baud Rate Timer
Refer to the following when using the baud rate timer to set the UART transfer
speed.
(1) Specifying the timer clock source
The clock source is specified by the TM3CKS3 to 1 flags of the timer 3
mode register (TM3MD).
(2) Setting the compare register
The compare register value is set in the timer 3 compare register (TM3OC).
This set value is computed according to the following formula:
overflow period = (compare register set value + 1) × timer clock period
baud rate = 1/(overflow period × 2 × 8)
SC0MD1(SC0CKM)
compare register set value = timer clock frequency/(baud rate × 2 × 8) – 1
Table 5-3-1 UART Transfer Rate
Example:
The timer 3 clock source is fs/4 (fosc = 8MHz) and a baud rate of 300 bps is
desired.
Since fs=fosc/2,
compare register set value = (8 × 10
6
/2/4)/(300 × 2 × 8) – 1
=207
= X'CF'
Chapter 5 Serial Functions
105
Half-duplex UART Serial Interface
4.0
fosc
(MHz)
Transfer Speed
(bps)
fosc
fs/4
fs/16
104
Set
Value
Calculated
Value
Set
Value
Calculated
Value
Set
Value
Calculated
Value
Set
Value
Calculated
Value
Set
Value
Calculated
Value
Set
Value
Calculated
Value
300
208
1202
104
2403
52
4807
26
9615
13
19230
109
300
218
1201
109
2402
55
4761
27
9699
208
300
52
1201
208
2404
104
4807
52
9615
26
19230
218
300
55
1190
218
2403
109
4805
55
9523
27
19398
78
300
78
1202
39
2403
156
4808
78
9615
39
19230
104
300
104
1202
52
2404
208
4808
104
9615
52
19230
109
300
109
1201
55
2381
218
4805
109
9610
55
19045
130
300
130
1202
65
2404
33
4735
130
9615
65
19231
fosc
fs/4
fs/16
fosc
fs/4
fs/16
fosc
fs/4
fs/16
fosc
fs/4
fs/16
fosc
fs/4
fs/16
fosc
fs/4
fs/16
fosc
fs/4
fs/16
300 1200 2400 4800 9600 19200
4.19
8.0
8.38
12.0
16.0
16.76
20.0
Set the values from this table
(minus 1) in the compare
register.