st20-gp6 STMicroelectronics, st20-gp6 Datasheet - Page 86

• Manufacturer Part Number: st20-gp6
• Description: Gps Processor
• Manufacturer: STMicroelectronics

ST20-GP6
The baud rate and the required reload value for a given baud rate can be determined by the follow-
ing formulae:
where: <ASCBaudRate> represents the content of the ASCBaudRate register, taken as unsigned
Table 15.3 lists various commonly used baud rates together with the required reload values and the
rounded deviation errors for an example baud rate with a CPU clock of 32.736 MHz.
15.4 Interrupt control
The ASC has a single interrupt coming out of it, called ASC_interrupt. The status bits in the ASC-
Status register determine the cause of the interrupt. ASC_interrupt will go high when a status bit
is 1 (high) and the corresponding bit in the ASCIntEnable register is 1.
Note the status register cannot be written to directly by software. The reset mechanism for the sta-
tus register is described below.
The following diagram illustrates the situation.
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38400
28800
19200
14400
9600
4800
2400
1200
600
300
75
Baud rate
16-bit integer,
f
CPU
is the frequency of the CPU.
53.28125
71.04167
106.5625
142.0833
213.125
426.25
852.5
1705
3410
6820
27280
Reload value
(exact)
<ASCBaudRate> = (
Baudrate =
Table 15.3 Baud rates
53
71
107
142
213
426
853
1705
3410
6820
27280
Reload value
(integer)
16 (<ASCBaudRate>)
16 x Baudrate
f
CPU
f
CPU
)
35
47
6B
8E
D5
1AA
355
6A9
D52
1AA4
6A90
Reload value
(hex)
-0.53%
-0.06%
0.41%
-0.06%
-0.06%
-0.06%
0.06%
0.00%
0.00%
0.00%
0.00%
Deviation error