Toshiba TLCS-90 Series Data Book page 240

TOSHIBA
TMP90C840
Table 3.3 (2) shows the relation between the transfer mode and the
result of updating the destination/source addresses.
Table 3.3 (2) Addresses Updated by Micro DMA Processing
Transfer
mode
Function \Destination\ Source \
\ address \ address \
000 I-byte transfer: Fix the current source/ \ 0 \ 0
001
010
011
100
101
110
III
destination addresses \ \
I-byte transfer: Increment the destination\ + 1
address \
I-byte transfer: Increment the source
address
I-byte transfer: Decrement the source
\
\
\
address \
2-byte transfer: Fix the current source/ \
destination addresses \
2-byte transfer: Increment the destination\
address \
2-byte transfer: Increment the source
address
2-byte transfer: Decrement the source
address
\
\
\
\
o
o
o
+
2
o
o
In the 2-byte transfer mode, data are transferred as follows:
(Destination address)
(Destination address+l)
<-
(Source address)
<-
(Source address+l)
o
+
1
- 1
o
o
+ 2
- 2
Similar data transfers are made in the modes that "decrement the
source address", but the updated results are different as shown in the
table 3.3 (2).
Fig. 3.3 (5) shows an example of the micro DMA processing that handles
data receiving of internal serial I/O.
This is an example of executing "an interrupt processing program after
serial data receiving" after receiving 7-frame data (Assume 1 frame
=
1 byte for this example) and saving them into the memory addresses
from FFOOH to FF06H.
MPU90-42