MC68HC08GZ32 Datasheet, PDF (138/320 Pages) Freescale Semiconductor, Inc – Microcontrollers

MSCAN08 Controller (MSCAN08)
TSEG22–TSEG10 — Time Segment
Time segments within the bit time fix the number of clock cycles per bit time and the location of the
sample point. Time segment 1 (TSEG1) and time segment 2 (TSEG2) are programmable as shown in
Table 12-8.
The bit time is determined by the oscillator frequency, the baud rate prescaler, and the number of time
quanta (T_q) clock cycles per bit as shown in Table 12-4).
Pres value
Bit time =
• number of time quanta
f_MSCANCLK
NOTE
The CBTR1 register can only be written if the SFTRES bit in the MSCAN08
module control register is set.
Table 12-8. Time Segment Values
TSEG13 TSEG12 TSEG11 TSEG10
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
.
.
.
.
.
.
.
.
1
1
1
1
Time
Segment 1
1 T_q Cycle⁽¹⁾
2 T_q Cycles⁽¹⁾
3T_q Cycles⁽¹⁾
4 T_q Cycles
.
.
16 T_q Cycles
TSEG22 TSEG21
0
0
0
0
.
.
.
.
1
1
1. This setting is not valid. Please refer to Table 12-4 for valid settings.
TSEG20
0
1
.
.
1
Time
Segment 2
1 T_q Cycle⁽¹⁾
2 T_q Cycles
.
.
8T_q Cycles
12.13.5 MSCAN08 Receiver Flag Register (CRFLG)
All bits of this register are read and clear only. A flag can be cleared by writing a 1 to the corresponding
bit position. A flag can be cleared only when the condition which caused the setting is valid no more.
Writing a 0 has no effect on the flag setting. Every flag has an associated interrupt enable flag in the
CRIER register. A hard or soft reset will clear the register.
Address: $0504
Bit 7
6
5
4
3
2
1
Bit 0
Read:
WUPIF RWRNIF TWRNIF RERRIF TERRIF BOFFIF OVRIF
RXF
Write:
Reset: 0
0
0
0
0
0
0
0
Figure 12-20. Receiver Flag Register (CRFLG)
WUPIF — Wakeup Interrupt Flag
If the MSCAN08 detects bus activity while in sleep mode, it sets the WUPIF flag. If not masked, a
wakeup interrupt is pending while this flag is set.
1 = MSCAN08 has detected activity on the bus and requested wakeup.
0 = No wakeup interrupt has occurred.
1. In this case PHASE_SEG1 must be at least 2 time quanta.
MC68HC08GZ32 Data Sheet, Rev. 3
138
Freescale Semiconductor