mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 132

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

Enhanced Serial Communications Interface (ESCI) Module
PDS2–PDS0 — Prescaler Divisor Select Bits
PSSB4–PSSB0 — Clock Insertion Select Bits
132
These read/write bits select the prescaler divisor as shown in
These read/write bits select the number of clocks inserted in each 32 output cycle frame to achieve
more timing resolution on the average prescaler frequency as shown in
The setting of ‘000’ will bypass not only this prescaler but also the prescaler
divisor fine adjust (PDFA). It is not recommended to bypass the prescaler
while ENSCI is set, because the switching is not glitch free.
PSSB[4:3:2:1:0]
0 0 0 0 0
0 0 0 0 1
0 0 0 1 0
0 0 0 1 1
0 0 1 0 0
0 0 1 0 1
0 0 1 1 0
0 0 1 1 1
0 1 0 0 0
0 1 0 0 1
0 1 0 1 0
0 1 0 1 1
0 1 1 0 0
0 1 1 0 1
0 1 1 1 0
PDS[2:1:0]
Table 13-9. ESCI Prescaler Divisor Fine Adjust
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
Table 13-8. ESCI Prescaler Division Ratio
MC68HC908QB8 Data Sheet, Rev. 2
0/32 = 0
1/32 = 0.03125
2/32 = 0.0625
3/32 = 0.09375
4/32 = 0.125
5/32 = 0.15625
6/32 = 0.1875
7/32 = 0.21875
8/32 = 0.25
9/32 = 0.28125
10/32 = 0.3125
11/32 = 0.34375
12/32 = 0.375
13/32 = 0.40625
14/32 = 0.4375
Prescaler Divisor Fine Adjust (PDFA)
NOTE
Prescaler Divisor (PD)
Bypass this prescaler
2
3
4
5
6
7
8
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Table
13-8.
Table
13-9.
Freescale Semiconductor