Serial Communication Interface (S12SCIV6)
MC9S12VRP Family Reference Manual Rev. 1.3
334
NXP Semiconductors
The transmitting device can address messages to selected receivers by including addressing information
in the initial frame or frames of each message.
The WAKE bit in SCI control register 1 (SCICR1) determines how the SCI is brought out of the standby
state to process an incoming message. The WAKE bit enables either idle line wakeup or address mark
wakeup.
10.4.6.6.1
Idle Input line Wakeup (WAKE = 0)
In this wakeup method, an idle condition on the RXD pin clears the RWU bit and wakes up the SCI. The
initial frame or frames of every message contain addressing information. All receivers evaluate the
addressing information, and receivers for which the message is addressed process the frames that follow.
Any receiver for which a message is not addressed can set its RWU bit and return to the standby state. The
RWU bit remains set and the receiver remains on standby until another idle character appears on the RXD
pin.
Idle line wakeup requires that messages be separated by at least one idle character and that no message
contains idle characters.
The idle character that wakes a receiver does not set the receiver idle bit, IDLE, or the receive data register
full flag, RDRF.
The idle line type bit, ILT, determines whether the receiver begins counting logic 1s as idle character bits
after the start bit or after the stop bit. ILT is in SCI control register 1 (SCICR1).
10.4.6.6.2
Address Mark Wakeup (WAKE = 1)
In this wakeup method, a logic 1 in the most significant bit (MSB) position of a frame clears the RWU bit
and wakes up the SCI. The logic 1 in the MSB position marks a frame as an address frame that contains
addressing information. All receivers evaluate the addressing information, and the receivers for which the
message is addressed process the frames that follow.Any receiver for which a message is not addressed
can set its RWU bit and return to the standby state. The RWU bit remains set and the receiver remains on
standby until another address frame appears on the RXD pin.
The logic 1 MSB of an address frame clears the receiver’s RWU bit before the stop bit is received and sets
the RDRF flag.
Address mark wakeup allows messages to contain idle characters but requires that the MSB be reserved
for use in address frames.
NOTE
With the WAKE bit clear, setting the RWU bit after the RXD pin has been
idle can cause the receiver to wake up immediately.
10.4.7
Single-Wire Operation
Normally, the SCI uses two pins for transmitting and receiving. In single-wire operation, the RXD pin is
disconnected from the SCI. The SCI uses the TXD pin for both receiving and transmitting.
Содержание MC9S12VRP64
Страница 16: ...MC9S12VRP Family Reference Manual Rev 1 3 16 NXP Semiconductors ...
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 ...
Страница 531: ...Package Information MC9S12VRP Family Reference Manual Rev 1 3 NXP Semiconductors 531 ...
Страница 532: ...Package Information MC9S12VRP Family Reference Manual Rev 1 3 532 NXP Semiconductors ...