Operation Of Hsdma; Operation In Dual-Address Mode - Epson S1C33210 Technical Manual

Operation of HSDMA

An HSDMA channel starts data transfer by the selected trigger factor.
Make sure that transfer conditions and a trigger factor are set and the HSDMA channel is enabled before starting a
DMA transfer.

Operation in Dual-Address Mode

In dual-address mode, both the source and destination addresses are accessed according to the bus condition set by
the BCU.
HSDMA has three transfer modes, in each of which data transfer operates differently. The following describes the
operation of HSDMA in each transfer mode.
Single transfer mode
The channel for which DxMOD in control information is set to "00" operates in single transfer mode. In this
mode, a transfer operation invoked by one trigger is completed after transferring one data unit of the size set by
DATSIZEx. If a data transfer needs to be performed a number of times as set by the transfer counter, an equal
number of triggers are required.
The operation of HSDMA in single transfer mode is shown by the flow chart in Figure 2.3.
(1) When a trigger is accepted, the trigger flag HSx_TF is cleared and then data of the size set in the control
information is read from the source address.
(2) The read data is written to the destination address.
(3) The addresses are incremented or decremented according to the SxIN/DxIN settings.
(4) The transfer counter is decremented.
(5) The HSDMA enable bit HSx_EN is cleared and HSDMA interrupt factor flag in ITC is set when the
transfer counter reaches 0 (when DINTENx = "1").
S1C33210 FUNCTION PART
START
Clear trigger flag HSx_TF
to accept next trigger
Data read from source
(1 byte or 1 half word)
Data write to destination
(1 byte or 1 half word)
Increment/decrement
address
Transfer counter - 1
Transfer
counter = 0
Y
Clear HSDMA enable bit
HSx_EN
Set interrupt factor flag
FHDMx
END
Figure 2.3 Operation Flow in Single Transfer Mode
EPSON
V DMA BLOCK: HSDMA (High-Speed DMA)
: according to SxIN/DxIN
settings
N
B-V-2-9