NXP Semiconductors PXN2020 - Page 1018

Enhanced Serial Communication Interface (eSCI)
PXN20 Microcontroller Reference Manual, Rev. 1
31-28 Freescale Semiconductor
triggered by the module are shown in Table 31-24. The state diagram of the transmitter is shown in
Figure 31-25.
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).
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.
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.
Table 31-22. Transmitter States
State
Indication
Description
eSCI_CR1[TE] eSCI_IFSR1[TACT]
Idle 0 0 Transmitter is disabled and no transmission is running
Ready 1 0 Transmitter is enabled and no transmission is running
Run 1 1 Transmitter is enabled and transmission is running
Stop 0 1 Transmitter is disabled and transmission is running
Table 31-23. Transmitter Application Transitions
Transition Command Condition Action Description
EN eSCI_CR1[TE] = 1 eSCI_CR1[TE] = 0 iPRE:= 1 Transmitter is enabled by application command.
DIS eSCI_CR1[TE]:= 0 eSCI_CR1[TE] = 1 Transmitter is disabled by application command
Ready
EN
start
Idle
RESET_STATE
Run
Stop
DIS
DIS
EN
halt
done