HD6412320 RENESAS [Renesas Technology Corp], HD6412320 Datasheet - Page 372

• Manufacturer Part Number: HD6412320
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family H8S-2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 8 Data Transfer Controller
Chain Transfer when Counter = 0: By executing a second data transfer, and performing re-
setting of the first data transfer, only when the counter value is 0, it is possible to perform 256 or
more repeat transfers.
An example is shown in which a 128-kbyte input buffer is configured. The input buffer is assumed
to have been set to start at lower address H'0000. Figure 8.13 shows the memory map.
[1] For the first transfer, set the normal mode for input data. Set fixed transfer source address
[2] Prepare the upper 8-bit addresses of the start addresses for each of the 64k transfer start
[3] For the second transfer, set repeat mode (with the source side as the repeat area) for re-setting
[4] Execute the first data transfer 64k times by means of interrupts. When the transfer counter for
[5] Next, execute the first data transfer the 64k times specified for the first data transfer by means
[6] Steps [4] and [5] are repeated endlessly. As repeat mode is specified for the second data
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(G/A, etc.), CRA = H'0000 (64k times), and CHNE = 1, CHNS = 1, and DISEL = 0.
addresses for the first data transfer in a separate area (in ROM, etc.). For example, if the input
buffer comprises H'200000 to H'21FFFF, prepare H'21 and H'20.
the transfer destination address for the first data transfer. Use the upper 8 bits of DAR in the
first register information area as the transfer destination. Set CHNE = DISEL = 0. If the above
input buffer is specified as H'200000 to H'21FFFF, set the transfer counter to 2.
the first data transfer reaches 0, the second data transfer is started. Set the upper 8 bits of the
transfer source address for the first data transfer to H'21. The lower 16 bits of the transfer
destination address of the first data transfer and the transfer counter are H'0000.
of interrupts. When the transfer counter for the first data transfer reaches 0, the second data
transfer is started. Set the upper 8 bits of the transfer source address for the first data transfer to
H'20. The lower 16 bits of the transfer destination address of the first data transfer and the
transfer counter are H'0000.
transfer, an interrupt request is not sent to the CPU.