MC9S12HZ256 Datasheet, PDF (392/692 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 13 Serial Communication Interface (SCIV4)
13.3.2.1 SCI Baud Rate Registers (SCIBDH and SCIBDL)
R
W
Reset
7
IREN
0
6
TNP1
5
TNP0
4
SBR12
3
SBR11
2
SBR10
0
0
0
0
0
Figure 13-3. SCI Baud Rate Register High (SCIBDH)
1
SBR9
0
0
SBR8
0
Table 13-1. SCIBDH Field Descriptions
Field
Description
7
IREN
Infrared Enable Bit — This bit enables/disables the infrared modulation/demodulation submodule.
0 IR disabled
1 IR enabled
6:5
Transmitter Narrow Pulse Bits — These bits determine if the SCI will transmit a 1/16, 3/16, 1/32, or 1/4 narrow
TNP[1:0] pulse. Refer to Table 13-3.
4:0
SBR[11:8]
SCI Baud Rate Bits — The baud rate for the SCI is determined by the bits in this register. The baud rate is
calculated two different ways depending on the state of the IREN bit.
The formulas for calculating the baud rate are:
When IREN = 0 then,
SCI baud rate = SCI module clock / (16 x SBR[12:0])
When IREN = 1 then,
SCI baud rate = SCI module clock / (32 x SBR[12:1])
R
W
Reset
7
SBR7
0
6
SBR6
5
SBR5
4
SBR4
3
SBR3
2
SBR2
0
0
0
0
1
Figure 13-4. SCI Baud Rate Register Low (SCIBDL)
1
SBR1
0
0
SBR0
0
Table 13-2. SCIBDL Field Descriptions
Field
Description
7:0
SBR[7:0]
SCI Baud Rate Bits — The baud rate for the SCI is determined by the bits in this register. The baud rate is
calculated two different ways depending on the state of the IREN bit.
The formulas for calculating the baud rate are:
When IREN = 0 then,
SCI baud rate = SCI module clock / (16 x SBR[12:0])
When IREN = 1 then,
SCI baud rate = SCI module clock / (32 x SBR[12:1])
Read: anytime
MC9S12HZ256 Data Sheet, Rev. 2.04
392
Freescale Semiconductor