Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV2)
302
MC9S12C-Family / MC9S12GC-Family
Freescale Semiconductor
Rev 01.24
10.3.2.7
MSCAN Transmitter Flag Register (CANTFLG)
The transmit buffer empty flags each have an associated interrupt enable bit in the CANTIER register.
NOTE
The CANTFLG register is held in the reset state when the initialization
mode is active (INITRQ = 1 and INITAK = 1). This register is writable when
not in initialization mode (INITRQ = 0 and INITAK = 0).
Read: Anytime
Write: Anytime for TXEx flags when not in initialization mode; write of 1 clears flag, write of 0 is ignored
1
OVRIE
Overrun Interrupt Enable
0
No interrupt request is generated from this event.
1
An overrun event causes an error interrupt request.
0
RXFIE
Receiver Full Interrupt Enable
0
No interrupt request is generated from this event.
1
A receive buffer full (successful message reception) event causes a receiver interrupt request.
1. WUPIE and WUPE (see
Section 10.3.2.1, “MSCAN Control Register 0 (CANCTL0)
”) must both be enabled if the recovery
mechanism from stop or wait is required.
2. Bus-off state is defined by the CAN standard (see Bosch CAN 2.0A/B protocol specification: for only transmitters. Because the
only possible state change for the transmitter from bus-off to TxOK also forces the receiver to skip its current state to RxOK,
the coding of the RXSTAT[1:0] flags define an additional bus-off state for the receiver (see
Section 10.3.2.5, “MSCAN Receiver
Module Base + 0x0006
7
6
5
4
3
2
1
0
R
0
0
0
0
0
TXE2
TXE1
TXE0
W
Reset:
0
0
0
0
0
1
1
1
= Unimplemented
Figure 10-10. MSCAN Transmitter Flag Register (CANTFLG)
Table 10-10. CANRIER Register Field Descriptions (continued)
Field
Description
Summary of Contents for MC9S12C Family
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