Fujitsu MB90895 Series Hardware Manual page 102

CHAPTER 3 CPU
I Buffer address pointer (BAP)
The buffer address pointer (BAP) is a 24-bit register and sets the 16-MB addresses where data is transferred
to or from I/O area. When the BAP updating/fixing select bit of the EI
to updated (ISCS: BF=0), the buffer address pointer (BAP) changes only in the lower 16 bits (BAPH,
BAPL) and does not change in the higher 8 bits (BAPH). Figure 3.5-14 shows the configuration of the
buffer address pointer (BAP).
bit23
BAP
R/W: Read/Write
X : Undefined
Reference: • The area that can be set by the I/O address pointer (IOA) is "000000
• The area that can be set by the buffer address pointer (BAP) is "000000
• The maximum transfer count that can be set by the data counter (DCT) is 65,536.
84
Figure 3.5-14 Configuration of Buffer Address Pointer (BAP)
bit16 bit15
BAPH
R/W
bit8 bit7
BAPM BAPL
R/W R/W
2
OS status register (ISCS: BF) is set
bit0
Reset value
XXXXXX
H
" to "00FFFF ".
H H
" to "FFFFFF ".
H H