CHAPTER 14 PORT FUNCTIONS
User’s Manual U14359EJ4V0UM
502
14.3.15 Port BD
Port BD is a 4-bit I/O port that can be set to the input or output mode in 1-bit units.
7
6
5
4
3
2
1
0
Address
After reset
PBD
–
–
–
–
PBD3
PBD2
PBD1
PBD0
FFFFF012H
Undefined
Bit position
Bit name
Function
3 to 0
PBDn
(n = 3 to 0)
Port BD
I/O port
In addition to their function as port pins, the port BD pins operate as the DMA acknowledge signal outputs in the
control mode.
(1) Operation in control mode
Port
Alternate Function Pin Name
Remark
Block Type
Port BD
PBD0 to
PBD3
DMAAK0 to DMAAK3
DMA acknowledge signal output
J
(2) I/O mode/control mode setting
The port BD I/O mode setting is performed by the port BD mode register (PMBD), and the control mode
setting is performed by the port BD mode control register (PMCBD).
(a) Port BD mode register (PMBD)
This register can be read/written in 8-bit or 1-bit units.
7
6
5
4
3
2
1
0
Address
After reset
PMBD
1
1
1
1
PMBD3
PMBD2
PMBD1
PMBD0
FFFFF032H
FFH
Bit position
Bit name
Function
3 to 0
PMBDn
(n = 3 to 0)
Port Mode
Specifies input/output mode for PBDn pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)
