D12320VF25IV Datasheet, PDF (957/1304 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 21 Power-Down Modes
21.2.3 Module Stop Control Register (MSTPCR)
MSTPCRH
MSTPCRL
Bit
: 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Initial value : 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1
R/W
: R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
MSTPCR is a 16-bit readable/writable register that performs module stop mode control.
MSTPCR is initialized to H'3FFF by a reset and in hardware standby mode. It is not initialized in
software standby mode.
Bits 15 to 0—Module Stop (MSTP15 to MSTP0): These bits specify module stop mode. See
table 21.3 for the method of selecting on-chip supporting modules.
Bits 15 to 0
MSTP15 to MSTP0
0
1
Description
Module stop mode cleared
Module stop mode set
21.3 Medium-Speed Mode
When the SCK2 to SCK0 bits in SCKCR are set to 1, the operating mode changes to medium-
speed mode as soon as the current bus cycle ends. In medium-speed mode, the CPU operates on
the operating clock (φ/2, φ/4, φ/8, φ/16, or φ/32) specified by the SCK2 to SCK0 bits. The bus
masters other than the CPU (the DMAC* and DTC) also operate in medium-speed mode. On-chip
supporting modules other than the bus masters always operate on the high-speed clock (φ).
In medium-speed mode, a bus access is executed in the specified number of states with respect to
the bus master operating clock. For example, if φ/4 is selected as the operating clock, on-chip
memory is accessed in 4 states, and internal I/O registers in 8 states.
Medium-speed mode is cleared by clearing all of bits SCK2 to SCK0 to 0. A transition is made to
high-speed mode and medium-speed mode is cleared at the end of the current bus cycle.
If a SLEEP instruction is executed when the SSBY bit in SBYCR is cleared to 0, a transition is
made to sleep mode. When sleep mode is cleared by an interrupt, medium-speed mode is restored.
Rev.6.00 Sep. 27, 2007 Page 925 of 1268
REJ09B0220-0600