HD6433937 Datasheet, PDF (123/521 Pages) Hitachi Semiconductor – Hardware Manual

5.6 Subactive Mode
5.6.1 Transition to Subactive Mode
Subactive mode is entered from watch mode if a timer A, timer F, timer G, IRQ₀, or WKP₇ to
WKP0 interrupt is requested while the LSON bit in SYSCR1 is set to 1. From subsleep mode,
subactive mode is entered if a timer A, timer C, timer F, timer G, SCI1, SCI31, SCI32, IRQ₄ to
IRQ₀, or WKP₇ to WKP₀ interrupt is requested. A transition to subactive mode does not take place
if the I bit of CCR is set to 1 or the particular interrupt is disabled in the interrupt enable register.
5.6.2 Clearing Subactive Mode
Subactive mode is cleared by a SLEEP instruction or by a low input at the RES pin.
• Clearing by SLEEP instruction
If a SLEEP instruction is executed while the SSBY bit in SYSCR1 is set to 1 and TMA3 bit in
TMA is set to 1, subactive mode is cleared and watch mode is entered. If a SLEEP instruction is
executed while SSBY = 0 and LSON = 1 in SYSCR1 and TMA3 = 1 in TMA, subsleep mode is
entered. Direct transfer to active mode is also possible; see 5.8, Direct Transfer, below.
• Clearing by RES pin
Clearing by RES pin is the same as for standby mode; see 2. Clearing by RES pin in 5.3.2,
Clearing Standby Mode.
5.6.3 Operating Frequency in Subactive Mode
The operating frequency in subactive mode is set in bits SA1 and SA0 in SYSCR2. The choices
are ø_W/2, ø_W/4, and ø_W/8.
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