PXN20RM Datasheet, PDF (1018/1376 Pages) Freescale Semiconductor, Inc – PXN20 Microcontroller

Enhanced Serial Communication Interface (eSCI)
triggered by the module are shown in Table 31-24. The state diagram of the transmitter is shown in
Figure 31-25.
halt
Stop
EN
RESET_STATE
Idle
EN
DIS
done
Run
DIS
Ready
start
Figure 31-25. Transmitter State Diagram
The current state of the transmitter can be determined by the TE control bit in the eSCI Control Register 1
(eSCI_CR1) and the TACT status bit in eSCI Interrupt Flag and Status Register 1 (eSCI_IFSR1).
Table 31-22. Transmitter States
State
Idle
Ready
Run
Stop
Indication
eSCI_CR1[TE] eSCI_IFSR1[TACT]
Description
0
0
Transmitter is disabled and no transmission is running
1
0
Transmitter is enabled and no transmission is running
1
1
Transmitter is enabled and transmission is running
0
1
Transmitter is disabled and transmission is running
The application triggers a transition described in Table 31-23 when it issues a command by writing to the
TE bit in the eSCI Control Register 1 (eSCI_CR1). The transition is triggered only if the conditions are
fulfilled. As a result of the transition the state of the transmitter is changed as shown in Figure 31-25 and
the action given in Table 31-23 is executed.
Table 31-23. Transmitter Application Transitions
Transition
EN
DIS
Command
Condition
eSCI_CR1[TE] = 1 eSCI_CR1[TE] = 0
eSCI_CR1[TE]:= 0 eSCI_CR1[TE] = 1
Action
iPRE:= 1
Description
Transmitter is enabled by application command.
Transmitter is disabled by application command
The module transition shown in Table 31-24 are triggered when the described condition or event occurs.
The send break bit SBK in the eSCI Control Register 1 (eSCI_CR1) is checked for the start condition. The
internal commit bit iCMT, the transmitter active bit TACT in the eSCI Interrupt Flag and Status Register 1
(eSCI_IFSR1), the TDRE, and the TC flag in the eSCI Interrupt Flag and Status Register 1 (eSCI_IFSR1)
are changed as a action result of the transition.
31-28
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor