II CORE BLOCK: ITC (Interrupt Controller)

A-1

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).

SIO2ES0: SIO Ch.2 receive error/FP0 interrupt factor switching

(D0) / Interrupt factor FP function switching register (0x402C5)

Switches the interrupt factor.

Write "1": SIO Ch.2 receive error

Write "0": FP0 input

Read: Valid

Set to "1" to use the SIO Ch.2 receive error interrupt.

Set to "0" to use the FP0 input interrupt.

At power-on, this bit is set to "0".

SIO2RS0: SIO Ch.2 receive-buffer full/FP1 interrupt factor switching (D1) / Interrupt factor FP function switching register (0x402C5)

Switches the interrupt factor.

Write "1": SIO Ch.2 receive-buffer full

Write "0": FP1 input

Read: Valid

Set to "1" to use the SIO Ch.2 receive-buffer full interrupt.

Set to "0" to use the FP1 input interrupt.

At power-on, this bit is set to "0".

SIO3ES0: SIO Ch.3 receive error/FP2 interrupt factor switching

(D2) / Interrupt factor FP function switching register (0x402C5)

Switches the interrupt factor.

Write "1": SIO Ch.3 receive error

Write "0": FP2 input

Read: Valid

Set to "1" to use the SIO Ch.3 receive error interrupt.

Set to "0" to use the FP2 input interrupt.

At power-on, this bit is set to "0".

B-II

ITC

S1C33L03 FUNCTION PART

EPSON

B-II-5-21