
4 ADDRESS MAP
4-2
EPSON
S1C17 FAMILY S1C17 CORE MANUAL
4.2 Processor Information in the Core I/O Area
The reserved core I/O area contains the processor information described below.
4.2.1 Trap Table Base Register (TTBR, 0xffff80)
Name
Address
Register name
Bit
Function
Setting
Init. R/W
Remarks
0x0
0x0–0xFFFD00
(256 byte units)
–
TTBR23
|
TTBR0
D31–24
D23
|
D0
Unused (fixed at 0)
Trap table base address
TTBR[7:0] is fixed at 0x0.
0x0
R
Initial value is set by
the TTBR pins of the
C17 macro.
FFFF80
(L)
Trap table
base register
This is a read-only register that contains the trap table base address.
The trap table (also called a vector table) contains the vectors to the interrupt handler routines (handler routine start
address) that will be read by the S1C17 Core to execute the handler when an interrupt occurs. The boot address
from which the program starts running after a reset must be written to the top of the trap table.
4.2.2 Processor ID Register (IDIR, 0xffff84)
Name
Address
Register name
Bit
Function
Setting
Init. R/W
Remarks
0x10
IDIR7
|
IDIR0
D7
|
D0
Processor ID
0x10: S1C17 Core
0x10
R
FFFF84
(B)
Processor ID
register
This is a read-only register that contains the ID code to represent a processor model. The S1C17 Core’s ID code is
0x10.
4.2.3 Debug RAM Base Register (DBRAM, 0xffff90)
Name
Address
Register name
Bit
Function
Setting
Init. R/W
Remarks
0x0
0x0–0xFFFDC0
(64 byte units)
–
DBRAM23
|
DBRAM0
D31–24
D23
|
D0
Unused (fixed at 0)
Debug RAM base address
DBRAM[5:0] is fixed at 0x0.
0x0
R
Initial value is set in
the C17 RTL-define
DBRAM_BASE.
FFFF90
(L)
Debug RAM
base register
This is a read-only register that contains the start address of a work area (64 bytes) for debugging.
In addition to the above registers, the reserved core I/O area contains some registers for debugging. For the debug
registers, refer to Section 6.5, “Debug Circuit.”