APPENDIX D BOOT
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
AP-D-5
(5) Reads 512 bytes of executable codes.
The executable codes are loaded from the beginning of IRAM (0x100–).
(6) Jumps to address 0x100 to execute the loaded codes.
Figure D.3.2.2 shows MBR reading start sequences for an SPI-EEPROM.
#CS (P02)
(if necessary)
CLK (USI_CK)
D (USI_DO)
Q (USI_DI)
D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5
READ command (0x03)
32-bit address
(0x00
×
4 bytes)
MBR data
0 1 2 3 4 5 6 7 8 9 10
36 37 38 39
40 41 42 43 44 45
Invalid data
Data 1
Data 2
3.2.2 EEPROM Read
Figure D.
EEPROM Data
D.3.3
The SPI-EEPROM boot sequence issues a 32-bit address regardless of the EEPROM size. Depending on the EE-
PROM size, data may be output during an address output period. Therefore, MBR codes must be followed by an
appropriate offset. The boot sequence ignores the offset bytes.
Table D.3.3.1 and Figure D.3.3.1 show the data locations according to the EEPROM size.
3.3.1 EEPROM Size and Address Size
Table D.
EEPROM size
Address size
MBR data location
1 to 256 bytes
1 byte
4th byte to 256th byte
0.25K to 64K bytes
2 bytes
3rd byte to 514th byte
64K to 16M bytes
3 bytes
2nd byte to 513th byte
16M to 4G bytes
4 bytes
1st byte to 512th byte
Byte 1
253-byte executable code
Invalid
Byte 2
Byte 3
Byte 4
Byte 5
· · ·
Byte 255
Byte 256
1-cycle address EEPROM
Byte 1
512-byte executable code
Invalid
Byte 2
Byte 3
Byte 4
Byte 5
· · ·
Byte 514
· · ·
2-cycle address EEPROM
Byte 1
512-byte executable code
Invalid
Byte 2
Byte 3
Byte 4
Byte 5
· · ·
Byte 513
· · ·
3-cycle address EEPROM
Byte 1
512-byte executable code
Byte 2
Byte 3
Byte 4
Byte 5
· · ·
Byte 512
· · ·
4-cycle address EEPROM
3.3.1 Data Location According to the EEPROM Size
Figure D.