Motorola MPC8260 - Manual (Page 714)

26-18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
must be even. For instance, the pointer to 8-bit data, 1 start, and 1 stop characters can be
even or odd, but the pointer to 9-bit data, 1 start, and 1 stop characters must be even. The
buffer can reside in internal or external memory.
26.3.11 SMC UART Event Register (SMCE)/Mask Register (SMCM)
The SMC event register (SMCE) generates interrupts and report events recognized by the
SMC UART channel. When an event is recognized, the SMC UART controller sets the
corresponding SMCE bit. Bits are cleared by writing a 1; writing 0 has no effect. The SMC
mask register (SMCM) has the same bit format as SMCE. Setting an SMCM bit enables,
and clearing it disables, the corresponding interrupt. All unmasked bits must be cleared
before the CP clears the internal interrupt request.
Table 26-9 describes SMCE/SMCM Þelds.
Figure 26-10 shows an example of the timing of various events in the SMCE.
Bit 0 1 2 3 4 5 6 7
Field Ñ BRKE Ñ BRK Ñ BSY TXB RXB
Reset 0
R/W R/W
Address 0x11A86 (SMCE1), 0x11A96 (SMCE2)/ 0x11A8A (SMCM1), 0x11A9A (SMCM2)
Figure 26-9. SMC UART Event Register (SMCE)/Mask Register (SMCM)
Table 26-9. SMCE/SMCM Field Descriptions
Bits Name Description
0 Ñ Reserved, should be cleared.
1 BRKE Break end. Set no sooner than after one idle bit is received after the break sequence.
2 Ñ Reserved, should be cleared.
3 BRK Break character received. Set when a break character is received. If a very long break sequence
occurs, this interrupt occurs only once after the Þrst all-zeros character is received.
4 Ñ Reserved, should be cleared.
5 BSY Busy condition. Set when a character is received and discarded due to a lack of buffers. Set no
sooner than the middle of the last stop bit of the Þrst receive character for which there is no available
buffer. Reception resumes when an empty buffer is provided.
6 TXB Tx buffer. Set when the transmit data of the last character in the buffer is written to the transmit FIFO.
Wait two character times to ensure that data is completely sent over the transmit signal.
7 RXB Rx buffer. Set when a buffer is received and its associated RxBD is closed. Set no sooner than the
middle of the last stop bit of the last character that is written to the receive buffer.