III PERIPHERAL MODULES 1 (SYSTEM): CLOCK MANAGEMENT UNIT (CMU)
III-1-20
EPSON
S1C33E07 TECHNICAL MANUAL
(2) Control register clock (SRAMSAPB_CLK)
This clock (MCLK) is used to control the SRAMC registers located in area 6. This clock is required for
accessing the SRAMC registers and it can be stopped when not in use. SRAMSAPB_CKE (D7/0x301B04) is
used for clock supply control (default: on).
SRAMSAPB_CKE: SRAMC SAPB Bus Interface Clock Control Bit in the Gated Clock Control Register 1
(D7/0x301B04)
III.1.9.6 Clock Supply to the GPIO
The CMU provides the clock paths with a control bit shown below for the GPIO. The clock supply turns on when
the control bit is set to 1 and it turns off when the control bit is set to 0.
(1) GPIO clock (PORT_CLK)
This clock (MCLK) is used for the GPIO circuit and is required for accessing the GPIO control registers.
GPIO_CKE (D8/0x301B04) is used for clock supply control (default: on).
GPIO_CKE: GPIO Normal Clock Control Bit in the Gated Clock Control Register 1 (D8/0x301B04)
(2) GPIO no stop clock (PORT_NOSTOP_CLK)
This clock (MCLK) is used for reading input ports and generating input interrupts. This clock can be
automatically turned off in HALT mode (see Section III.1.9.2) by setting GPIONSTP_HCKE (D27/0x301B04)
to 0 (default: on).
GPIONSTP_HCKE: GPIO No Stop Clock Control (HALT) Bit in the Gated Clock Control Register 1
(D27/0x301B04)
Note, however, that the GPIO no stop clock is required in HALT mode when using an input interrupt to cancel
HALT mode.
III.1.9.7 Clock Supply to the EFSIO
The CMU provides the clock paths with a control bit shown below for the EFSIO. The clock supply turns on when
the control bit is set to 1 and it turns off when the control bit is set to 0.
(1) Control register clock (EFSIOSAPB_CLK)
This clock (MCLK) is used to control the EFSIO registers located in area 6. This clock is required for accessing
the EFSIO registers and it can be stopped when not in use. EFSIOSAPB_CKE (D5/0x301B04) is used for clock
supply control (default: on).
EFSIOSAPB_CKE: EFSIO SAPB Bus Interface Clock Control Bit in the Gated Clock Control Register 1
(D5/0x301B04)
(2) EFSIO baud rate timer clock (EFSIO_BAUDRATE_CLK)
This clock (MCLK) is used as the source clock for the baud rate timer in EFSIO. This clock can be
automatically turned off in HALT mode (see Section III.1.9.2) by setting EFSIOBR_HCKE (D25/0x301B04) to
0 (default: on).
EFSIOBR_HCKE: EFSIO Baud Rate Clock Control (HALT) Bit in the Gated Clock Control Register 1
(D25/0x301B04)
III.1.9.8 Clock Supply to the USB
The CMU provides the clock paths with the control bit shown below for the USB module. The clock supply turns
on when the control bit is set to 1 and it turns off when the control bit is set to 0.
(1) USB clock (USB_CLK)
This clock (OSC3 = 48 MHz) is used for the USB interface module. USB_CKE (D8/0x301B00) is used for
clock supply control (default: off).
USB_CKE: USB IP 48 MHz Clock Control Bit in the Gated Clock Control Register 0 (D8/0x301B00)