Panasonic MN101C77C - Manual (Page 465)

Operation
Chapter 14 Automatic Transfer Controller
XIV - 27
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In transfer mode 9, ATC1 executes a data byte transfer twice each time it is activated. However, the
value in memory pointer 0 increments by one only after the first transfer ends. As a result, the source
address for the next ATC1 operation is one address higher than that for the previous operation.
Set the data transfer count for ATC1 in the transfer data counter (AT1TRC). The counter can be set to a
maximum of 255 transfers. The counter decrements each time ATC1 is activated (after one byte of data
has been transferred twice). When it reaches x'00', an interrupt (ATC1IRQ) occurs and the automatic
transfer ends.
Transfer mode 9 can be used to support continuous transmission/ reception for serial inter-
face 0 and 1. Set the memory pointer 1 to point to the serial reception buffer (RXBUF0,
RXBUF1) and select serial interrupts as the ATC1 trigger factor. In this way, each the serial
communication ends, the MCU continuously reads the reception data (first data byte trans-
fer), then writes the transmission data to the transmission buffer (TXBUF0, TXBUF1) (sec-
ond data byte transfer) up to 255 times, entirely through the hardware.
Before execute a continuous serial transaction, store the serial transmission data in the
memory space that memory pointer 0 points, once the serial communication ends, the MCU
has written to the reception data over the transmission data, so that only reception data
remains in the memory.