Ch.0 receive-buffer full interrupt: Ch.0 transmit-buffer empty interrupt: Ch.1 receive-buffer full interrupt: Ch.1 transmit-buffer empty interrupt:

III PERIPHERAL BLOCK: SERIAL INTERFACE

The interrupt priority register sets the interrupt priority level of each interrupt source in a range between 0 and

7. An interrupt request to the CPU is accepted only when no other interrupt request of a higher priority has been generated.

In addition, only when the PSR's IE bit = "1" (interrupts enabled) and the set value of the IL is smaller than the input interrupt level set by the interrupt priority register, will the input interrupt request actually be accepted by the CPU.

For details on these interrupt control registers, as well as the device operation when an interrupt has occurred, refer to "ITC (Interrupt Controller)".

•Ch.2 and Ch.3

Ch.2 and Ch.3 do not have dedicated interrupt signals. Either a port input interrupt or 16-bit timer interrupt is selected, and interrupt handling is performed accordingly.

The correspondence between port input interrupt factors and 16-bit timer interrupt factors is shown in Table.8.10.

Table 8.10 Correspondence between Interrupt Factors

Serial I/F Ch.2, Ch.3/

Port input interrupt

16-bit timer interrupt

T8-Ch.4, Ch.5 interrupt factor

factor

factor

T8 Ch.5 UF

FPT7

Timer 2 compare A

T8 Ch.4 UF

FPT5

Timer 2 compare B

SIO Ch.3 TXD Emp.

FPT6

Timer 4 compare A

SIO Ch.3 RXD Full

FPT4

Timer 4 compare B

SIO Ch.3 RXD Err.

FPT2

Timer 3 compare A

SIO Ch.2 TXD Emp.

FPT3

Timer 5 compare A

SIO Ch.2 RXD Full

FPT1

Timer 5 compare B

SIO Ch.2 RXD Err.

FPT0

Timer 3 compare B

Switching between the above interrupt factors is performed by means of the interrupt factor FP function switching register (0x402C5) and the interrupt factor TM16 function switching register (0x402CB).

For the setting of the interrupt controller in the CPU-core, the setting for the selected interrupt factor is used. Refer to the "ITC (Interrupt Controller)" section in the Core Block Manual for details of interrupts, and the "Input/Output Ports" and "16-Bit Timers" sections in the Peripheral Circuit Block Manual for details of port input interrupt factor and 16-bit timer interrupt factor settings.

Intelligent DMA

•Ch.0 and Ch.1

The receive-buffer full interrupt and transmit-buffer empty interrupt factors can be used to invoke intelligent DMA (IDMA). This enables successive transmit/receive operations between memory and the

transmit/receive-buffer to be performed by means of a DAM transfer.

The following shows the IDMA channel numbers set for each interrupt factor: IDMA Ch.

0x17

0x18

0x19

0x1A

The IDMA request and enable bits shown in Table 8.11 must be set to "1" for IDMA to be invoked. Transfer conditions, etc. on the IDMA side must also be set in advance.

Table 8.11 Control Bits for IDMA Transfer

Channel

Interrupt factor

IDMA request bit

IDMA enable bit

Ch.0

Receive-buffer full

RSRX0(D6/0x40292)

DESRX0(D6/0x40296)

 

Transmit-buffer empty

RSTX0(D7/0x40292)

DESTX0(D7/0x40296)

Ch.1

Receive-buffer full

RSRX1(D0/0x40293)

DESRX1(D0/0x40297)

 

Transmit-buffer empty

RSTX1(D1/0x40293)

DESTX1(D1/0x40297)

S1C33210 FUNCTION PART

EPSON

B-III-8-25