User manual

RS232-ADC16/24
8.4 Reaction time
Reaction time depends on two things – the baud rate and system clock of
course. Each request has to be received and decoded before any action could
occure. The overhead of decoding is partly time-shared with pure transmission
overhead thus falling less and less in account in either higher system clock
rates or slower transmission speed.
Note that transmission and decoding overhead do not account the main time
when making more precise ADC measurements.
The following data considers a scenario were the time between sending a
command (e.g. switching a pin's level) and the end of execution (pin has
changed to this level) might be critical.
Response time
f
SYSCLK
in MHz time in μs
6.125 4383
12.25 2937
24.5 2711
49 2551
This data is collected at 115200 baud not involving time needed for receiving
the request's answer.
3 6,1 12,2 49
0
1000
2000
3000
4000
5000
CLOCK vs response time
time in μs
CLOCK in MHz
response time
The task was to set the level of D
0
low. Time measurement started when
sending the request and stopped when D
0
had become low triggered by
interrupt. The length of the request was 14 bytes. According to this, time
needed for transmission would be 1215 μs at 115200 baud.
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