29 MISC REGISTERS (MISC)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
29-3
Control Register Details
29.6
6.1 List of Misc Registers
Table 29.
Address
Register name
Function
0x300010
MISC_RTCWT
RTC Wait Control Register
Configure RTC access cycles
0x300012
MISC_USB
USB Configuration Register
Enable USB interrupt and configure access cycle
0x300014
MISC_RAMWT
Internal RAM Wait Control Register
Configure IRAM and IVRAM access cycles
0x300016
MISC_BOOT
Boot Register
Indicate/set boot conditions
0x300018
MISC_RAM_LOC
RAM Location Select Register
Select area for locating RAM
0x300020
MISC_PROTECT
Misc Protect Register
Enable/disable Misc register write protection
The Misc registers are described in detail below. These are 8-bit registers.
Note: The Misc registers at addresses 0x300010–0x300018 are write-protected. Before the Misc regis-
ters can be rewritten, write protection of these registers must be removed by writing data 0x96 to
PROT[7:0]/MISC_PROTECT register. Note that since unnecessary rewrites to the Misc registers
could lead to erratic system operation, PROT[7:0] should be set to other than 0x96 unless the
Misc registers must be rewritten.
RTC Wait Control Register (MISC_RTCWT)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
RTC Wait
Control Register
(MISC_RTCWT)
0x300010
(8 bits)
D7–3 –
reserved
–
–
–
0 when being read.
D2–0 RTCWT[2:0] RTC register access wait control
0 to 7 cycles
0x7 R/W Write-protected
D[7:3]
Reserved
D[2:0]
RTCWT[2:0]: RTC Register Access Wait Control Bits
Sets the number of wait cycles to be inserted when accessing the RTC control register.
6.2 RTCWT[2:0] (RTC Wait Cycle) Settings
Table 29.
RTCWT[2:0]
Number of wait cycles
MCLK frequency
0x7
7 cycles
f
MCLK
≤
60 MHz
0x6
6 cycles
0x5
5 cycles
0x4
4 cycles
0x3
3 cycles
0x2
2 cycles
0x1
1 cycle
0x0
0 cycles
Cannot be set
(Note)
(Default: 0x7)
The number of wait cycles should be set according to the MCLK clock frequency.
Note: The S1C33L26 RTC cannot operate if RTCWT[2:0] is set to 0x0 (0 wait cycles).
USB Configuration Register (MISC_USB)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
USB
Configuration
Register
(MISC_USB)
0x300012
(8 bits)
D7
–
reserved
–
–
–
0 when being read.
D6
USBINTEN USB interrupt enable
1 Enable
0 Disable
0
R/W Write-protected
D5
USBSNZ
USB snooze control
1 Enable
0 Disable
0
R/W
D4–3 –
reserved
–
–
–
0 when being read.
D2–0 USBWT[2:0] USB register access wait control
0 to 7 cycles
0x7 R/W Write-protected
D7
Reserved
D6
USBINTEN: USB Interrupt Enable Bit
Enables or disables USB interrupts.
1 (R/W): Interrupt enabled
0 (R/W): Interrupt disabled (default)
For more information on the causes of USB interrupts, see the “USB Function Controller (USB)” chap-
ter.