![NXP Semiconductors MC9S08PA4 Reference Manual Download Page 161](http://html1.mh-extra.com/html/nxp-semiconductors/mc9s08pa4/mc9s08pa4_reference-manual_1721838161.webp)
FLL lock and clock monitor
8.2.3.1 FLL clock lock
In FBE and FEE modes, the clock detector source uses the external reference as the
reference. When FLL is detected from lock to unlock, the ICS_S[LOLS] bit is set. An
interrupt will be generated if ICS_C4[LOLIE] bit is set. ICS_S[LOLS] bit is cleared by
reset or by writing a logic 1 to ICS_S[LOLS] when ICS_S[LOLS] is set. Writing a logic
0 to ICS_S[LOLS] has no effect.
In FBI and FEI modes, the lock detector source uses the internal reference as the
reference. When FLL is detected from lock to unlock, the ICS_S[LOLS] bit is set. An
interrupt will be generated if ICS_S[LOLS] bit is set. ICS_S[LOLS] bit is cleared by
reset or by writing a logic 1 to ICS_S[LOLS] when ICS_S[LOLS] is set. Writing a logic
0 to ICS_S[LOLS] has no effect.
In FBELP and FBILP modes, the FLL is not on, therefore, lock detect function is not
applicable.
8.2.3.2 External reference clock monitor
In FBE, FEE, FEI, or FBI modes, if ICS_C4[CME] bit is written to 1, the clock monitor
is enabled. If the external reference falls below a certain frequency, such as f
loc_high
or
f
loc_low
depending on the ICS_OSCSC[RANGE] bit, the MCU will reset. The
SYS_SRS[CLK] bit will be set to indicate the error.
In FBELP or FBILP modes, the FLL is not on, so the external reference clock monitor
will not function even if ICS_C4[CME] bit is written to 1.
External reference clock monitor uses FLL as the internal reference clock. The FLL must
be functional before ICS_C4[CME] bit is set.
8.3 Initialization / application information
This section provides example code to give some basic direction to a user on how to
initialize and configure the ICS module. The example software is implemented in C
language.
8.2.3
Chapter 8 Clock management
MC9S08PA4 Reference Manual, Rev. 5, 08/2017
NXP Semiconductors
161
Summary of Contents for MC9S08PA4
Page 1: ...MC9S08PA4 Reference Manual Supports MC9S08PA4 Document Number MC9S08PA4RM Rev 5 08 2017 ...
Page 2: ...MC9S08PA4 Reference Manual Rev 5 08 2017 2 NXP Semiconductors ...
Page 22: ...MC9S08PA4 Reference Manual Rev 5 08 2017 22 NXP Semiconductors ...
Page 28: ...System clock distribution MC9S08PA4 Reference Manual Rev 5 08 2017 28 NXP Semiconductors ...
Page 150: ...Port data registers MC9S08PA4 Reference Manual Rev 5 08 2017 150 NXP Semiconductors ...
Page 196: ...Human machine interfaces HMI MC9S08PA4 Reference Manual Rev 5 08 2017 196 NXP Semiconductors ...
Page 224: ...Instruction Set Summary MC9S08PA4 Reference Manual Rev 5 08 2017 224 NXP Semiconductors ...
Page 232: ...Functional Description MC9S08PA4 Reference Manual Rev 5 08 2017 232 NXP Semiconductors ...
Page 258: ...FTM Interrupts MC9S08PA4 Reference Manual Rev 5 08 2017 258 NXP Semiconductors ...
Page 294: ...Functional description MC9S08PA4 Reference Manual Rev 5 08 2017 294 NXP Semiconductors ...
Page 398: ...Resets MC9S08PA4 Reference Manual Rev 5 08 2017 398 NXP Semiconductors ...
Page 400: ...MC9S08PA4 Reference Manual Rev 5 08 2017 400 NXP Semiconductors ...