FUJITSU MB91460 SERIES FR60 - Manual (Page 208)

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Chapter 13 Clock Control
4.Registers
• After setting “11B” (subclock), insert one or more NOP instructions.
• Selecting the subclock as the clock source is prohibited while the subclock selection enable bit (SCKEN)
is “0”. (See table for details.)
Example: To select the subclock after an INIT reset, first write “01
B
” and then write “11
B
” (subclock).
(See “ 8. Caution (Page No.205) ”.)
Table 4-1 Cases When the CLKS1 and CLKS0 Bits May or May Not be Modified
Modify permitted Modify not permitted
“00”
→ “01” or “10”
“00”
→ “11”
“01”
→ “11” or “00”
“01”
→ “10”
“10”
→ “00”
“10”
→ “01” or “11”
“11” → “01” “11” → “00” or “10”