Samsung S3C6400X User Manual page 785

HOST INTERFACE
Repeated Burst Write to reduce the HOST CPU (ex. Modem) overhead
With 'Repeated Burst Write' and DMA, a large data of MP (Modem Processor) can be transferred to a
"Destination area". First, the CPU writes CTRL, DLEN, and SADDR in the CPUIF Client as shown in Figure 24-7.
Then, the CPU initializes the DMA with source information (i.e., the start address1 and data length2 of the large
data) and destination information (i.e., a 32b address, where the CPU interface3 is mapped). While the DMA
reads a large data from source and writes them into the CPU interface port, the CPU can execute the remaining
jobs. This scheme can be also applied to just 'Burst Write' and 'Burst Read', where the DMA handles only
payload part.
1
This start address is different from SADDR [31:0]. This start address is in the addressing space of MP(Modem
Processor) while SADDR is in the addressing space of AP(S3C6400).
2
This data length is same as DLEN.
3
This CPU interface or CPUIF Client is sometimes called as "Host Interface".
24-8
Preliminary product information describe products that are in development,
for which full characterization data and associated errata are not yet available.
Specifications and information herein are subject to change without notice.
Figure 24-8. Repeated Burst Write Procedure
S3C6400X
RISC MICROPROCESSOR