
2 CPU
S1C17003 TECHNICAL MANUAL
EPSON
2-7
CPU
2.4 Vector Table
The vector table contains the vectors (processing routine start addresses) for interrupt processing routines. When an
interrupt occurs, the S1C17 core reads the vector corresponding to the interrupt and executes that processing routine.
The boot address for starting program execution must be written at the top of the vector table after resetting.
The S1C17003 vector table starts from address 0x8000. The vector table base address can be read from the TTBR
(vector table base register) at address 0xffff80.
For more information on Vector Table, refer to “6. Interrupt Controller”
The base (top) address for the vector table for writing interrupt vectors can be set using the MISC_TTBRL and
MISC_TTBRH registers (0x5328 and 0x532a). The MISC_TTBRL and MISC_TTBRH registers are set to the
0x8000 address after initial resetting. This means only the reset vector must be written to the above address, even
when changing the vector table location. Bits 7 to 0 in the MISC_TTBRL register are fixed to 0; the initial address
of the vector table normally starts from the 256 byte boundary.
0x5328–0x532a: Vector Table Address Low/High Registers (MISC_TTBRL, MISC_TTBRH)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
Vector Table
Address Low
Register
(MISC_TTBRL)
0x5328
(16 bits)
D15–8 TTBR[15:8] Vector table base address A[15:8]
0x0–0xff
0x80 R/W
D7–0 TTBR[7:0]
Vector table base address A[7:0]
(fixed at 0)
0x0
R
Vector Table
Address High
Register
(MISC_TTBRH)
0x532a
(16 bits)
D15–8 –
reserved
–
0 when being read.
D7–0 TTBR[23:16] Vector table base address
A[23:16]
0x0–0xff
0x0 R/W
Note: The MISC_TTBRL and MISC_TTBRH registers are write-protected. To write to these registers,
write-protection must be overridden by writing 0x96 to the MISC Protect Register (0x5324).
Normally, the MISC Protect Register (0x5324) should be set to a value other than 0x96, except
when writing to the MISC_TTBRL and MISC_TTBRH registers, since unnecessary writes may
result in system malfunctions.