upd70f3402 Renesas Electronics Corporation., upd70f3402 Datasheet - Page 490

• Manufacturer Part Number: upd70f3402
• Description: 32-/16-bit Single-chip Microcontroller With Can Interface
• Manufacturer: Renesas Electronics Corporation.

14.3.12 Transmit Buffer Overflow Interrupt Signal (INTC3nO)
When the transmit FIFO buffer contains 16 elements, writing a 17th chip-select data (SFCS write) or
transfer data (SFDB write) results in the generation of the overflow interrupt INTC3nO. For the 17th
item, both chip-select and transfer data values are discarded.
The transmit FIFO buffer contains 16 elements if the FIFO pointer value for the write operation equals
the FIFO pointer value for the SIO load operation plus 15. When the transfer is completed and the FIFO
buffer pointer for the SIO load operation is incremented, space for one element is available again in
transmit buffer.
490
Transmit buffer -n+15
SIO load operation
Transmit buffer -n
Figure 14-24: Transmit Buffer Overflow Interrupt Signal (INTC3nO)
CPU Data Write
QCSI pointer for
pointer for write
QCSI Buffer
INTC3nO
:
SFFUL
f
QCSI
Chapter 14 Queued CSI (CSI30, CSI31)
User’s Manual U16702EE3V2UD00
SFDB write
data 15
data 0
n + 15
n
SFDB or SFCS write
data 16
data 15
n
created in Transmit Buffer
Transmission of data 0 is
completed and space is
n + 1