m5m51016btp Renesas Electronics Corporation., m5m51016btp Datasheet - Page 133

• Manufacturer Part Number: m5m51016btp
• Description: Renesas 16-bit Single-chip Microcomputer M16c Family / M16c/20 Series
• Manufacturer: Renesas Electronics Corporation.

M30245 Group
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
Operation
2.7.2 Operation of frequency synthesizer
The following explains how to setup after hardware reset. Table 2.7.1 to 2.7.3 show frequency synthe-
sizer related registers setting examples.
Table 2.7.1. Example of setting the frequency synthesizer prescaler register (FSP)
Prescaler
Clock f(X
When the frequency synthesizer prescaler register is set at 255, the prescaler is disabled and f
f(X
f
Note: The value of f
PIN
12 MH
1 MH
1 MH
2 MH
2 MH
3 MH
6 MH
IN
f
PIN
= f(X
). Table 2.7.1 shows some examples of how the frequency synthesizer prescaler register is set.
(1) Cancel the protect register.
(2) Set the frequency synthesizer related registers to generate the 48MHz clock that is necessary
(3) Enable the frequency synthesizer by setting frequency synthesizer control register.
(4) The protect register should be set to write disabled. A 3ms wait is necessary.
(5) The frequency synthesizer locked status bit should be checked. It is necessary to recheck
(6) Enable USB clock.
(7) After waiting four cycles of the
Z
Z
Z
Z
Z
Z
A minimum delay of 250ns is needed before performing any other USB related registers read/
Z
for the f
after a wait of 0.1ms if it is “0” (unlocked).
write operations.
IN
IN
) is prescaled down by the frequency synthesizer prescaler register (FSP) to generate f
) / 2(n+1) n: FSP value
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USB
PIN
.
FSP Value
255 (FF
Dec (Hex)
should not be set below 1 MHz.
7 (07
5 (05
3 (03
2 (02
1 (01
0 (00
16
16
16
16
16
16
16
)
)
)
)
)
)
)
or greater, the USB enable bit should be set to “1”.
12.00 MH
16.00 MH
12.00 MH
16.00 MH
12.00 MH
12.00 MH
12.00 MH
fX
(IN)
Z
Z
Z
Z
Z
Z
Z
2. Frequency synthesizer (PLL)
PIN
PIN
=
.