RX610 Group
13. Data Transfer Controller (DTC)
R01UH0032EJ0120 Rev.1.20
Page 340 of 1006
Feb 20, 2013
13.2.5
DTC Transfer Count Register A (CRA)
Notes: 1. The function depends on transfer mode.
2. x: Undefined
Address (inaccessible directly from the CPU)
b4
b15
b8
b7
b3
b2
b1
b0
b14
b13
b12
b11
b10
b9
b6
b5
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
b4
b15
b8
b7
b3
b2
b1
b0
b14
b13
b12
b11
b10
b9
b6
b5
•
Normal transfer mode
CRA
•
Repeat transfer mode/block transfer mode
CRAH
CRAL
Value after reset:
Value after reset:
Symbol
Register Name
Description
R/W
CRAL
Transfer Counter A Lower Register
Set transfer count.
CRAH
Transfer Counter A Upper Register
Note: Set CRAH and CRAL to the same value in repeat transfer mode and block transfer mode.
CRA is used to set the transfer count of the DTC.
The function of this register depends on transfer mode.
CRA cannot be accessed directly from the CPU.
(1)
Normal transfer mode (MD[1:0] bits in MRA = 00b)
CRA functions as a 16-bit transfer counter in normal transfer mode.
The transfer count is 1, 65535, and 65536 when the set value is 0001h, FFFFh, and 0000h, respectively.
The CRA value is decremented (-1) at each data transfer.
(2)
Repeat transfer mode (MD[1:0] bits in MRA = 01b)
The CRAH register retains transfer count and the CRAL register functions as an 8-bit transfer counter.
The transfer count is 1, 255, and 256 when the set value is 01h, FFh, and 00h, respectively.
The CRAL value is decremented (-1) at each data transfer. When it reaches 00h, the CRAH value is transferred to CRAL.
(3)
Block transfer mode (MD[1:0] bits in MRA = 10b)
The CRAH register retains block size and the CRAL register functions as an 8-bit block size counter.
The transfer count is 1, 255, and 256 when the set value is 01h, FFh, and 00h, respectively.
The CRAL value is decremented (-1) at each data transfer. When it reaches 00h, the CRAH value is transferred to CRAL.