29 MISC REGISTERS (MISC)
29-2
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
USB Settings
29.3
USB Wait Control
29.3.1
The MISC_USB register contains USBWT[2:0] to set the number of wait cycles to be inserted when accessing the
USB registers. The number of wait cycles should be set according to the MCLK clock frequency.
3.1.1 USBWT[2:0] (USB Wait Cycle) Settings
Table 29.
USBWT[2:0]
Number of wait cycles
MCLK frequency
0x7
7 cycles
f
MCLK
≤
60 MHz
0x6
6 cycles
f
MCLK
≤
56 MHz
0x5
5 cycles
f
MCLK
≤
45 MHz
0x4
4 cycles
f
MCLK
≤
36 MHz
0x3
3 cycles
f
MCLK
≤
24 MHz
0x2
2 cycles
f
MCLK
≤
16 MHz
0x1
1 cycle
f
MCLK
< 8 MHz
0x0
0 cycles
(Default: 0x7)
Snooze Control
29.3.2
The MISC_USB register contains USBSNZ that controls Snooze mode for the USB function controller. Setting
USBSNZ to 1 enables Snooze mode.
Refer to the “USB Function Controller (USB)” chapter for details on control of the USB function controller.
USB Interrupt Enable
29.3.3
The MISC_USB register contains USBINTEN that enables or disables the USB function controller to generate in-
terrupts. Setting USBINTEN to 1 enables USB interrupts; setting to 0 disables USB interrupts.
RAM Location
29.4
The MISC_RAM_LOC register contains IVRAM_LOC to select the IVRAM location and DSTRAM_CFG to se-
lect the DSTRAM location.
IVRAM is located in Area 3 by default (IVRAM_LOC = 1) and is used as the internal VRAM. Setting IVRAM_
LOC to 0 relocates IVRAM in Area 0 and it can be used as a general-purpose RAM.
DSTRAM is located in Area 3 by default (DSTRAM_CFG = 0) and is used as a general-purpose RAM. Setting
DSTRAM_CFG to 1 relocates it to the LCDC module as LUTRAM (look-up table RAM). In this case LUTRAM
cannot be accessed by the CPU.
Boot Register
29.5
The MISC_BOOT register is used to confirm the boot device and configure #CE10 boot conditions.
BOOT[3:0] indicates the boot device that has been specified by the BOOT pin.
5.1 BOOT[3:0] Bits
Table 29.
BOOT[3:0]
Boot mode
0b1000
SPI/RS232C boot
0b0100
NOR Flash/external ROM boot
Other
Reserved
The MISC_BOOT register contains another control bit BOOT_ENA that is used for the booting process by the in-
ternal boot sequencer.
Note: When programming a Flash memory on the target board, BOOT_ENA must be set to 0. Be sure
to avoid changing the boot mode when writing data to the MISC_BOOT register.
For more information on booting, see “Boot” in Appendix.