
II CORE BLOCK: ITC (Interrupt Controller)
B-II-5-20
EPSON
S1C33L01 FUNCTION PART
DENONLY: IDMA enable register set method selection
(D2) / Flag set/reset method select register (0x4029F)
Select the method for setting the IDMA enable registers.
Write "1": Set-only method
Write "0": Read/write method
Read: Valid
With the set-only method, IDMA enable bits are set by writing "1".
The IDMA enable bits for which "0" has been written can neither be set nor reset. Therefore, this method ensures
that only a specific IDMA enable bit is set. However, when using read-modify-write instructions (e.g., bset, bclr, or
bnot), note that an IDMA enable bit that has been set to "1" is not reset by writing.
The read/write method is selected by writing "0" to DENONLY. When this method is selected, IDMA enable bits
can be read and written as for other registers. Therefore, the IDMA enable bit is reset by writing "0" and set by
writing "1". In this case all IDMA enable bits for which "0" has been written are reset. Even in a read-modify-write
operation, an interrupt enable bit can be reset by the hardware between the read and the write, so be careful when
using this method.
After an initial reset, DENONLY is set to "1" (set-only method).
TBRP7–TBRP0: TTBR register write protection ([D[7:0]) / TTBR write-protect register (0x4812D)
Remove write protection for the TTBR register.
Write 0x59: Write protection is removed
Write not the above: No operation (write protected)
Read: Valid
Before writing to the TTBR register, set TBRP to "0x59" to remove the write protection. Then when data is written
to the most significant byte (0x48137) of the TTBR, the register once again becomes write-protected.
After an initial reset, TBRP is set to "0x0" (write protected).
TTBR09–TTBR00: Trap table base address [9:0] (D[9:0]) / TTBR low-order register (0x48134[HW])
TTBR15–TTBR10: Trap table base address [15:10] (D[F:A]) / TTBR low-order register (0x48134[HW])
TTBR2B–TTBR20: Trap table base address [27:16] (D[B:0]) / TTBR high-order register (0x48136[HW])
TTBR33–TTBR30: Trap table base address [31:28] (D[F:C]) / TTBR high-order register (0x48136[HW])
Set the starting address of the trap table.
TTBR0 and TTBR3 are read-only registers and are fixed to "0". For this reason, the trap table starting address always
begins with a 1KB boundary address.
The TTBR registers normally are write-protected to prevent them from being inadvertently rewritten. To remove
this write protect function, another register, TBRP (D[F:8]) / TTBR write-protect register (0x4812D), is provided. A
write to the TTBR register is enabled by writing "0x59" to TBRP and is disabled back again by a write to the most
significant byte of the TTBR register (0x48137). Consequently, writes to the TTBR register need to begin with the
low-order half-word first. However, since occurrences of NMI and the like between writes of the low-order and
high-order half-words cause malfunctions, it is recommended that the register be written in words.
After an initial reset, the TTBR register is set to 0x0C00000.