APPENDIX D BOOT
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
AP-D-3
Bit 31
Reset vector
0
Bit 30
Bit 29
· · ·
Bit 3
Bit 2
Bit 1
Bit 0
16-bit device
Reset vector
1
8-bit device
0x20000000
Figure D.2.3.1 Reset Vector for NOR Flash/External ROM Boot
The LSB of the reset vector is ignored when the program jumps to the user reset handler routine. Therefore, the
jump destination is always a 16-bit boundary address even if the LSB is set to 1 for 8-bit boot.
SPI-EEPROM Boot
D.3
Configuration of SPI-EEPROM Boot System
D.3.1
When the S1C33L26 is turned on or reset with the BOOT and #CE10 pins set to 1 (HV
DD
), the S1C33L26 boots
up by executing the MBR after loading it from the EEPROM, FRAM, or Serial Flash connected to the SPI bus to
IRAM. Figure D.3.1.1 shows an SPI-EEPROM boot system connection diagram.
S1C33L26
EEPROM (SPI)
Reset signal
#CS
CLK
D
Q
#HOLD
#WP
#RESET
#CE10 (P53)
BOOT
P02
(P03) USI_CK
(P01) USI_DO
(P00) USI_DI
P
xx
#RESET
HV
DD
HV
DD
*
*
The BOOT and #CE10 pins must be pulled up with external resistors, as the #CE10 (P53) inter-
nal pull-up resistor is disabled.
3.1.1 SPI-EEPROM Boot System
Figure D.
3.1.1 Pins Used for SPI-EEPROM Boot
Table D.
S1C33L26 pin
EEPROM pin
Pin status before booting
Pin status after booting
P02/USI_CS/SCLK1/REMC_O
#CS
Input
High output
P00/
USI_DI/SIN1/#NAND_WR
Q
Input
Input
P01/
USI_DO/SOUT1/#NAND_RD
D
Input
Output
P03/
USI_CK/#SRDY1/REMC_I
CLK
Input
Low output
#RESET
#RESET
Input
Input
–
#HOLD
*
3
–
–
P
xx
*
1
#WP
(Input)
(Input)
#CE10/
P53
*
2
–
Input (pulled up internally)
Input
*
1 It should be controlled according to the application by the user program after booting.
*
2 Used to select SPI-EEPROM boot or PC RS232C boot during boot mode configuration with the BOOT pin.
*
3 Fix at high.
The pins listed in the table are configured for USI (SPI master mode) (pin names in
boldface
) in the boot se-
quence. Therefore, these pins cannot be used for general-purpose I/O or other peripheral functions.
This boot sequence supports up to 4GB (4-cycle address) of SPI-bus EEPROM. The SPI module is configured as
below in the boot sequence.
Bit rate:
OSC3 / 32 (e.g., 1.5 MHz when OSC3 = 48 MHz)
SPI mode:
SCPOL = 0, SCPHA = 0
Data bit length:
8 bits
Master/slave mode: Master mode