S12 Clock, Reset and Power Management Unit (S12CPMU_UHV_V8)
MC9S12VRP Family Reference Manual Rev. 1.3
NXP Semiconductors
167
4.7.2
Application information for COP and API usage
In many applications the COP is used to check that the program is running and sequencing properly. Often
the COP is kept running during Stop Mode and periodic wake-up events are needed to service the COP on
time and maybe to check the system status
.
For such an application it is recommended to use the ACLK as clock source for both COP and API. This
guarantees lowest possible IDD current during Stop Mode
.
Additionally it eases software implementation
using the same clock source for both, COP and API
.
The Interrupt Service Routine (ISR) of the Autonomous Periodic Interrupt API should contain the write
instruction to the CPMUARMCOP register. The value (byte) written is derived from the “main routine”
(alternating sequence of $55 and $AA) of the application software
.
Using this method, then in the case of a runtime or program sequencing issue the application “main
routine” is not executed properly anymore and the alternating values are not provided properly. Hence the
COP is written at the correct time (due to independent API interrupt request) but the wrong value is written
(alternating sequence of $55 and $AA is no longer maintained) which causes a COP reset
.
If the COP is stopped during any Stop Mode it is recommended to service the COP shortly before Stop
Mode is entered.
Содержание MC9S12VRP64
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Страница 46: ...Device Overview S12VRP Series MC9S12VRP Family Reference Manual Rev 1 3 46 NXP Semiconductors ...
Страница 92: ...Port Integration Module S12VRPPIMV1 MC9S12VRP Family Reference Manual Rev 1 3 92 NXP Semiconductors ...
Страница 106: ...S12G Memory Map Controller S12GMMCV1 MC9S12VRP Family Reference Manual Rev 1 3 106 NXP Semiconductors ...
Страница 192: ...Background Debug Module S12SBDMV1 MC9S12VRP Family Reference Manual Rev 1 3 192 NXP Semiconductors ...
Страница 236: ...S12S Debug Module S12DBGV2 MC9S12VRP Family Reference Manual Rev 1 3 236 NXP Semiconductors ...
Страница 244: ...Interrupt Module S12SINTV1 MC9S12VRP Family Reference Manual Rev 1 3 244 NXP Semiconductors ...
Страница 340: ...Serial Communication Interface S12SCIV6 MC9S12VRP Family Reference Manual Rev 1 3 340 NXP Semiconductors ...
Страница 358: ...Timer Module TIM16B2CV3 MC9S12VRP Family Reference Manual Rev 1 3 358 NXP Semiconductors ...
Страница 424: ...LIN Physical Layer S12LINPHYV2 MC9S12VRP Family Reference Manual Rev 1 3 424 NXP Semiconductors ...
Страница 436: ...Supply Voltage Sensor BATSV2 MC9S12VRP Family Reference Manual Rev 1 3 436 NXP Semiconductors ...
Страница 488: ...64 KByte Flash Module S12FTMRG64K4KV2 MC9S12VRP Family Reference Manual Rev 1 3 488 NXP Semiconductors ...
Страница 528: ...NVM Electrical Parameters MC9S12VRP Family Reference Manual Rev 1 3 528 NXP Semiconductors ...
Страница 529: ...MC9S12VRP Family Reference Manual Rev 1 3 NXP Semiconductors 529 Appendix J Package Information ...
Страница 530: ...Package Information MC9S12VRP Family Reference Manual Rev 1 3 530 NXP Semiconductors ...
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