Execute Transfer Count Registers (Etcr) - Renesas F-ZTAT H8 Series Hardware Manual

8.2.3

Execute Transfer Count Registers (ETCR)

An execute transfer count register (ETCR) is a 16-bit readable/writable register that specifies the
number of transfers to be executed. These registers function in one way in I/O mode and idle
mode, and another way in repeat mode.
• I/O mode and idle mode
15
Bit
Initial value
R/W
Read/Write
In I/O mode and idle mode, ETCR functions as a 16-bit counter. The count is decremented by
1 each time one transfer is executed. The transfer ends when the count reaches H'0000.
• Repeat mode
Bit
Initial value
Read/Write R/W
Bit
Initial value
Read/Write R/W
In repeat mode, ETCRH functions as an 8-bit transfer counter and ETCRL holds the initial
transfer count. ETCRH is decremented by 1 each time one transfer is executed. When ETCRH
reaches H'00, the value in ETCRL is reloaded into ETCRH and the same operation is repeated.
The ETCRs are not initialized by a reset or in standby mode.
14 13 12 11
R/W R/W R/W R/W R/W
7 6 5
R/W R/W
7 6 5
R/W R/W
10 9 8 7 6
Undetermined
R/W R/W R/W R/W
Transfer counter
4 3
Undetermined
R/W R/W
ETCRH
Transfer counter
4 3
Undetermined
R/W R/W
ETCRL
Initial count
Rev. 7.00 Sep 21, 2005 page 205 of 878
Section 8 DMA Controller
5 4 3 2
R/W R/W R/W R/W R/W
2 1
R/W R/W
2 1
R/W R/W
REJ09B0259-0700
1 0
R/W
0
R/W
0
R/W