
SP37
Tire Pressure Monitoring Sensor
ROM Library Functions
ROM Library Function Guide
75
Revision 1.0, 2011-12-15
2.15
StartXtalOsc()
2.15.1
Description
This function enables the crystal oscillator clock and delays for a defined amount of time. The delay time should
be long enough that the crystal oscillator is stable, which is determined by the crystal startup time (see
). The
minimum/maximum tolerance of the delay time may be derived by considering the tolerance of the
12 MHz RC Oscillator (see
).
2.15.2
Actions
•
Enable the crystal oscillator clock
•
Wait in IDLE for set Delay time
2.15.3
Prototype
signed char
StartXtalOsc
(unsigned char
Delay
)
2.15.4
Inputs
2.15.5
Outputs
2.15.6
Resource Usage
Table 70
StartXtalOsc: Input Parameters
Register / Address
Type
Name
Description
R7
unsigned char Delay
Delay time to wait in IDLE after XTAL is enabled.
Duration[µs] = Delay x 42.67[µs]
Table 71
StartXtalOsc: Output values
Register/Address
Type
Name
Description
R7
signed char
StatusByte
StatusByte:
0: XTAL started and delay passed
-1: XTAL already on (no action)
Table 72
StartXtalOsc: Resources
Type
Used or Modified
Registers
R7
SFR
ACC, B, CFG0, DPTR, DIVIC, PSW, REF, TCON, TH0, TL0, TMOD
Stack
0 Bytes
1)
1) Two additional bytes, not included here, are needed to call the library function