Telegraph Length Set Register (Dewr); Table 13.3.6A Number Of Transmit Data Bytes Setting - Fujitsu F2MC-16LX MB90580 Series Hardware Manual

13.3 Registers and Register Details

13.3.6 Telegraph length set register (DEWR)

Telegraph length set register (DEWR)
Address: 000074
H
Read/write
Initial value
This register is used to set the number of data bytes to be transmitted and is valid only for data
transmission.
During slave transmit, make sure to set the transmit data count byte to '1' when the control frame are 0H
(Reading Slave Status), 4H (Reading Lock-address of the lower 8-bit), 5H (Reading Lock-address of the
upper 8-bit), 6H (Reading slave -status and diabling lock).
If the no. of bytes required to transfer is greater than the maximum no of transfer byte per frame, it will
result in multiframe communciation. In that case, DEWR should be set using the following formula.
DEWR = DERR - Maximum no. of transfer bytes per frame
Upon the completion of one frame, the remaining number of byte required to transfer can be obtained by
deducting the maximum no. of transfer byte per frame from DERR. This value is used to set DEWR for the
next frame.
152 Chapter 13: IE Bus
7 6 5
DE7 DE6 DE5
(R/W) (R/W) (R/W)
(0) (0) (0)

Table 13.3.6a Number of transmit data bytes setting

DE7-0
01H
02H
..
..
FFH
00H
4 3
DE4 DE3
(R/W)
(R/W)
(0) (0)
Number of transmit data bytes
1 byte
2 bytes
..
..
255 bytes
256 bytes
2 1 0
DE2 DE1 DE0
(R/W) (R/W) (R/W)
(0) (0) (0)
Bit Number
DECR
MB90580 Series