HITACHI 185
source or destination. When RXI is set as the transfer request, however, the transfer source must
be the SCI’s receive data register (RDR). Likewise, when TXI is set as the transfer request, the
transfer source must be the SCI's transmit data register (TDR).
Table 9.4
Selecting On-Chip Peripheral Module Request Modes with the RS Bit
RS3
RS2 RS1
RS0
DMA
Transfer
Request
Source
DMA Transfer Request
Signal
Source
Desti-
nation
Bus Mode
0
1
0
0
SCI0
receiver
RXI0 (SCI0 receive data full
interrupt transfer request)
RDR0
Any*
Cycle steal
0
1
0
1
SCI0
trans-
mitter
TXI0 (SCI0 transmit data
empty interrupt transfer
request)
Any
TDR0
Cycle steal
0
1
1
0
SCI1
receiver
RXI1 (SCI1 receive data full
interrupt transfer request)
RDR1
Any*
Cycle steal
0
1
1
1
SCI1
trans-
mitter
TXI1 (SCI1 transmit data
empty interrupt transfer
request)
Any*
TDR1
Cycle steal
1
0
0
0
ITU0
IMIA0 (ITU0 input capture A/
compare-match A)
Any*
Any*
Burst/Cycle
steal
1
0
0
1
ITU1
IMIA1 (ITU1 input capture A/
compare-match A)
Any*
Any*
Burst/Cycle
steal
1
0
1
0
ITU2
IMIA2 (ITU2 input capture A/
compare-match A)
Any*
Any*
Burst/Cycle
steal
1
0
1
1
ITU3
IMIA3 (ITU3 input capture A/
compare-match A)
Any*
Any*
Burst/Cycle
steal
SCI0, SCI1: Serial communications interface channels 0 and 1
ITU0–ITU3: Channels 0–3 of the 16-bit integrated-timer pulse unit.
RDR0, RDR1: Receive data registers 0, 1 of SCI
TDR0, TDR1: Transmit data registers 0, 1 of SCI
Note:
External memory, memory-mapped external device, on-chip memory, on-chip peripheral
module (excluding DMAC)
When outputting transfer requests from on-chip peripheral modules, the appropriate interrupt
enable bits must be set to output the interrupt signals. Note that transfer request signals from on-
chip peripheral modules (interrupt request signals) are sent not just to the DMAC but to the CPU
as well. When an on-chip peripheral module is specified as the transfer request source, set the
priority level values in the interrupt priority level registers (IPRC–IPRE) of the interrupt controller
(INTC) at or below the levels set in the I3–I0 bits of the CPU’s status register (SR) so that the
CPU does not acknowledge the interrupt request signal.