
SP37
Tire Pressure Monitoring Sensor
ROM Library Functions
ROM Library Function Guide
62
Revision 1.0, 2011-12-15
2.9
Start_Supply_Voltage()
2.9.1
Description
The battery voltage typically shows a significant drop during RF transmission, when a considerable current is
drawn. Calling the monolithic function
during RF transmission is often not feasible
because of its execution time.
A set of three functions to allow battery voltage measurement during RF transmission has been implemented;
,
and
. These functions must be called
in this particular sequence, and each function is separately described in detail.
Start_Supply_Voltage() enables and configures the ADC, allows settling of the analogue ADC part, and places the
ADC into standby state. It must be called prior to calling the
function.
2.9.2
Actions
•
Prepare the ADC and the Supply Voltage Sensor for a measurement
2.9.3
Prototype
unsigned char
Start_Supply_Voltage
( void )
2.9.4
Inputs
2.9.5
Outputs
Table 46
Start_Supply_Voltage: Input Parameters
Register / Address
Type
Name
Description
None
---
---
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Table 47
Start_Supply_Voltage: Output values
Register/ Address
Type
Name
Description
R7
unsigned char Status Byte
Always returns 0