Panasonic MN101C77C, F77G user manual Transfer Mode

Chapter 14 Automatic Transfer Controller

14-3-9 Transfer Mode 4

In transfer mode 4, ATC1 automatically transfers two bytes (one word) of data from any memory space to the I/O space (special registers : x'03F00' - x'03FFF') every time an ATC1 activation request occurs.

(2)

(4)

Memory Pointer 0 00000 - 3FFFF

AT1MAP0

AT1MAP0 + 1

AT1MAP0 + 2

AT1MAP0 + 3

Memory Pointer 1 03F00 - 03FFF

(1) AT1MAP1 (even)

(2)

(3) AT1MAP1 (odd)

(Only lower

8 bits are valid)

Figure 14-3-6 Transfer Mode 4

Set the source address in 18-bit memory pointer 0 (AT1MAP0H, M, L), and set the destination I/O address in the lower 8 bits of memory pointer 1(AT1MAP1L). The upper 10 bits of the I/O space address (x'03F') need not to be set in AT1MAP1H and AT1MAP1M.

Always set an even address as the destination I/O address in memory pointer 1. When ATC1 transfers one word to the I/O space, ATC1 can transfer the even address set in memory pointer 1 and the odd address that immediately follows it.

In transfer mode 4, ATC1 executes a data byte transfer twice, to send one data word, each time it is activated. The value in memory pointer 0 increments by one each time a byte-length data transfer ends. As a result, the source address for the next ATC1 operation is two addresses higher than that for the previous operation.

In this word-length transfer, ATC1 transfers the first data byte to an even address in the I/O space and the second data byte to an odd address in the I/O space.

Set the data transfer data 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 each word transfer). When it reaches x'00', an interrupt (ATC1IRQ) occurs and the automatic transfer ends.

XIV - 18 Operation