mc9s12xs128 Freescale Semiconductor, Inc, mc9s12xs128 Datasheet - Page 432

• Manufacturer Part Number: mc9s12xs128
• Description: Hcs12 Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Communication Interface (S12SCIV5)
14.5.2.2
SCI operation in wait mode depends on the state of the SCISWAI bit in the SCI control register 1
(SCICR1).
14.5.2.3
The SCI is inactive during stop mode for reduced power consumption. The STOP instruction does not
affect the SCI register states, but the SCI bus clock will be disabled. The SCI operation resumes from
where it left off after an external interrupt brings the CPU out of stop mode. Exiting stop mode by reset
aborts any transmission or reception in progress and resets the SCI.
The receive input active edge detect circuit is still active in stop mode. An active edge on the receive input
can be used to bring the CPU out of stop mode.
14.5.3
This section describes the interrupt originated by the SCI block.The MCU must service the interrupt
requests.
432
RXEDGIF SCIASR1[7]
Interrupt
BERRIF
BKDIF
RDRF
TDRE
IDLE
OR
•
•
TC
If SCISWAI is clear, the SCI operates normally when the CPU is in wait mode.
If SCISWAI is set, SCI clock generation ceases and the SCI module enters a power-conservation
state when the CPU is in wait mode. Setting SCISWAI does not affect the state of the receiver
enable bit, RE, or the transmitter enable bit, TE.
If SCISWAI is set, any transmission or reception in progress stops at wait mode entry. The
transmission or reception resumes when either an internal or external interrupt brings the CPU out
of wait mode. Exiting wait mode by reset aborts any transmission or reception in progress and
resets the SCI.
Table 14-20
SCIASR1[1]
SCIASR1[0]
SCISR1[7]
SCISR1[6]
SCISR1[5]
SCISR1[3]
SCISR1[4]
Interrupt Operation
Source
Wait Mode
Stop Mode
lists the eight interrupt sources of the SCI.
Local Enable
RXEDGIE
BERRIE
BRKDIE
TCIE
ILIE
RIE
TIE
S12XS Family Reference Manual, Rev. 1.10
Table 14-20. SCI Interrupt Sources
Active high level. Indicates that a byte was transferred from SCIDRH/L to the
transmit shift register.
Active high level. Indicates that a transmit is complete.
Active high level. The RDRF interrupt indicates that received data is available
in the SCI data register.
Active high level. This interrupt indicates that an overrun condition has occurred.
Active high level. Indicates that receiver input has become idle.
Active high level. Indicates that an active edge (falling for RXPOL = 0, rising for
RXPOL = 1) was detected.
Active high level. Indicates that a mismatch between transmitted and received data
in a single wire application has happened.
Active high level. Indicates that a break character has been received.
Description
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