6 CLOCK MANAGEMENT UNIT (CMU)
6-20
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
D4
SDCLK_EN: SDCLK Clock Enable Bit
Enables or disables the SDCLK clock supply to the SRAMC and SDRAMC.
1 (R/W): Enabled (on) (default)
0 (R/W): Disabled (off)
The SDCLK_EN default setting is 1, which enables the clock supply. If the SRAMC and SDRAMC
modules can be stopped, disable the clock supply by setting SDCLK_EN to 0 to reduce current con-
sumption.
Note: When using the SDRAMC in double frequency mode (MCLK : SDCLK = 1 : 2), the SDRAMC
operates with SDCLK configured to double the frequency of MCLK, while the SRAMC oper-
ates on the same frequency as MCLK.
D3
BCLK_EN: BCLK Clock Enable (in HALT) Bit
Enables or disables the BCLK clock supply in HALT mode.
1 (R/W): Enabled (on) (default)
0 (R/W): Disabled (off)
The BCLK clock is used to operate the modules listed below.
• IVRAM (Area 3)
• DSTRAM (Area 3)
• SRAM controller (SRAMC)
• SDRAM controller (SDRAMC)
• DMA controller (DMAC)
• LCD controller (LCDC) bus interface
• Clock management unit (CMU) registers
• Bus arbiters
BCLK is required for bus and memory operations, therefore, it is always supplied to the modules listed
above in normal mode. However, the BCLK supply in HALT mode can be disabled to reduce current
consumption by setting BCLK_EN to 0 if the LCDC and DMA do not need bus operations.
D2
PCLK2_EN: PCLK2 Clock Enable Bit
Enables or disables the PCLK2 clock supply.
1 (R/W): Enabled (on) (default)
0 (R/W): Disabled (off)
The PCLK2 clock is used to operate the modules listed below.
• Prescaler (PSC Ch.1)
• 8-bit programmable timer Ch.1, 3, 5, 7 (T8 Ch.1, 3, 5, 7)
• Universal serial interface with LCD interface (USIL)
• Serial interface Ch.1 (FSIO Ch.1)
• Watchdog timer (WDT)
• Remote controller (REMC)
• Interrupt controller (ITC)
• I/O ports (GPIO)
• BBRAM
• Cache controller (CCU) registers
• Real-time clock (RTC) registers
• SRAM controller (SRAMC) registers
• SDRAM controller (SDRAMC) registers
• LCD controller (LCDC) registers
The PCLK2_EN default setting is 1, which enables the clock supply. If all the modules listed above can
be stopped, disable the clock supply by setting PCLK2_EN to 0 to reduce current consumption.