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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
PBD
–
–
Bit position
Bit name
3 to 0
PBDn
(n = 3 to 0)
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
Port BD
PBD0 to
DMAAK0 to DMAAK3
PBD3
(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
PMBD
1
1
Bit position
Bit name
3 to 0
PMBDn
(n = 3 to 0)
502
CHAPTER 14 PORT FUNCTIONS
5
4
3
–
–
PBD3
Port BD
I/O port
Alternate Function Pin Name
5
4
3
1
1
PMBD3
Port Mode
Specifies input/output mode for PBDn pin.
0: Output mode (output buffer on)
1: Input mode (output buffer off)
User's Manual U14359EJ4V0UM
2
1
0
PBD2
PBD1
PBD0
Function
Remark
DMA acknowledge signal output
2
1
0
PMBD2
PMBD1
PMBD0
Function
Address
After reset
FFFFF012H Undefined
Block Type
J
Address
After reset
FFFFF032H
FFH
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