HD64F7045F28V Datasheet, PDF (307/925 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7040 Series

Table 11.9 Transfer Conditions and Register Set Values for Transfer between A/D
Converter and On-Chip Memory
Transfer Conditions
Transfer source: on-chip A/D converter ch0
Transfer destination: on-chip memory
Transfer count: 128 times (reload count 32 times)
Transfer source address: incremented
Transfer destination address: incremented
Transfer request source: A/D converter
Bus mode: burst
Transfer unit: byte
Interrupt request generation at end of transfer
Channel priority ranking: 0 > 2 > 3 > 1
Register
SAR2
DAR2
DMATCR2
CHCR2
DMAOR
Value
H'FFFF83F0
H'FFFFF000
H'00000080
H'00085B25
H'0101
When address reload is on, the SAR value returns to its initially established value every four
transfers. In the above example, when a transfer request is input from the A/D converter, the byte
size data is first read in from the H'FFFF83F0 register of AD0 and that data is written to the on-
chip memory address H'FFFFF001. Because a byte size transfer was performed, the SAR and
DAR values at this point are H'FFFF83F1 and H'FFFFF001, respectively. Also, because this is a
burst transfer, the bus rights remain secured, so continuous data transfer is possible.
When four transfers are completed, if the address reload is off, execution continues with the fifth
and sixth transfers and the SAR value continues to increment from H'FFFF83F3 to H'FFFF83F4 to
H'FFFF83F5 and so on. However, when the address reload is on, the DMAC transfer is halted
upon completion of the fourth one and the bus right request signal to the CPU is cleared. At this
time, the value stored in SAR is not H'FFFF83F3–H'FFFF83F4, but H'FFFF83F3–H'FFFF83F0, a
return to the initially established address. The DAR value always continues to be decremented
regardless of whether the address reload is on or off.
The DMAC internal status, due to the above operation after completion of the fourth transfer, is
indicated in table 11.10 for both address reload on and off.
267