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SERIAL INTERFACE
12
12-8
32185/32186 Group Hardware Manual
Rev.1.10 REJ09B0235-0110 May 15, 07
Receive
DMA transfer request
RFIN
(Reception Finished bit)
Note: No reception-finished DMA transfer requests are generated if a receive error occurs.
Figure 12.2.4 Reception-finished DMA Transfer Request
(3) Selecting the source of an interrupt request
The interrupt request signals sent from each SIO to the Interrupt Controller (ICU) are broadly
classified into transmit interrupts and receive interrupts. Transmit interrupt requests can be gener-
ated when the transmit buffer is empty or transmission is finished, and the receive interrupt re-
quests can be generated when reception is finished or an receive error is detected, as selected by
the Interrupt Request Source Select Registers (SI03SEL, SI45SEL).
Notes: No interrupt request signals are generated unless interrupts are generated by the SIO
Interrupt Request Mask Register after enabling the TEN (Transmit Enable) bit or REN
(Receive Enable) bit for the corresponding SIO.
SIO2 and SIO3 together comprise one interrupt group, so do SIO4 and SIO5.
The transmission-finished interrupt is effective when the internal clock is selected in UART
or CSIO mode.
(4) Notes on using transmit interrupts
When the interrupt request is enable in SIO Interrupt Request Mask Register and the transmit
buffer empty interrupt is selected in SIO Interrupt Request Source Select Register, a transmit
interrupt request is generated upon enabling the corresponding TEN (Transmit Enable) bit.
(5) About DMA transfer requests from SIO
Each SIO can generate a transmit DMA transfer and a reception-finished DMA transfer request.
These DMA transfer requests can be generated by enabling each SIO’s corresponding TEN (Transmit
Enable) bit or REN (Receive Enable) bit. When using DMA transfers to communicate with external
devices, be sure to set the DMA Controller (DMAC) before enabling the TEN or REN bit. No reception-
finished DMA transfer requests are generated if a receive error occurs.
Transmit DMA transfer request
Generated when the transmit buffer is empty and the TEN bit is enabled.
TEN
(Transmit Enable bit)
TBE
(Transmit Buffer
Empty bit)
Transmit DMA
transfer request
Figure 12.2.3 Transmit DMA Transfer Request
Reception-finished DMA transfer request
A DMA transfer request is generated when the receive buffer is filled.
12.2 Serial Interface Related Registers