mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 133

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Use the following formula to calculate the ESCI baud rate:
where:
Table 13-10
Freescale Semiconductor
SCI clock source = bus clock or BUSCLKX4 (selected by ESCIBDSRC in the configuration register)
BPD = Baud rate register prescaler divisor
BD = Baud rate divisor
PD = Prescaler divisor
PDFA = Prescaler divisor fine adjust
shows the ESCI baud rates that can be generated with a 4.9152-MHz bus frequency.
Table 13-9. ESCI Prescaler Divisor Fine Adjust (Continued)
PSSB[4:3:2:1:0]
0 1 1 1 1
1 0 0 0 0
1 0 0 0 1
1 0 0 1 0
1 0 0 1 1
1 0 1 0 0
1 0 1 0 1
1 0 1 1 0
1 0 1 1 1
1 1 0 0 0
1 1 0 0 1
1 1 0 1 0
1 1 0 1 1
1 1 1 0 0
1 1 1 0 1
1 1 1 1 0
1 1 1 1 1
Baud rate =
MC68HC908QB8 Data Sheet, Rev. 2
Frequency of the SCI clock source
64 x BPD x BD x (PD + PDFA)
15/32 = 0.46875
16/32 = 0.5
17/32 = 0.53125
18/32 = 0.5625
19/32 = 0.59375
20/32 = 0.625
21/32 = 0.65625
22/32 = 0.6875
23/32 = 0.71875
24/32 = 0.75
25/32 = 0.78125
26/32 = 0.8125
27/32 = 0.84375
28/32 = 0.875
29/32 = 0.90625
30/32 = 0.9375
31/32 = 0.96875
Prescaler Divisor Fine Adjust (PDFA)
Registers
133