Input Resistor Registers (Rdr0 And Rdr1) - Fujitsu F2MC-16LX Hardware Manual
Mb90550a/b series, 16-bit
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Also See for F2MC-16LX:
- Hardware manual (706 pages) ,
- Application note (13 pages) ,
- Operation manual (10 pages)
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CHAPTER 7 I/O PORTS
7.3.4
Input Resistor Registers (RDR0 and RDR1)
An input resistor register (RDR0 and RDR1) controls a pull-up resistor in an input
mode.
■ Input Resistor Registers (RDR0 and RDR1)
Port 0 input resistor register
Address:00001C
Read/write
Initial value
Port 1 input resistor register
Address:00001D
Read/write
Initial value
Table 7.3-3 Function of the Input Resistor Registers (RDR0 and RDR1)
RDR0, RDR1
Notes:
• These registers have no meaning in an output mode. (Without a pull-up resistor)
• The data direction register (DDR) determines the I/O mode.
• The pull-up resistor is not provided during hardware standby and stop (SPL = 1)(high
impedance).
• This function is prohibited in an external bus mode. Do not write this register.
144
Figure 7.3-5 Input Resistor Registers (RDR0 and RDR1)
7
6
bit
RD07 RD06 RD05 RD04 RD03 RD02 RD01 RD00
H
(R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W)
(0)
(0)
7
6
bit
RD17 RD16 RD15 RD14 RD13 RD12 RD11 RD10
H
(R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W)
(0)
(0)
0
Without a pull-up resistor in an input mode [initial value]
1
With a pull-up resistor in an input mode
5
4
3
(0)
(0)
(0)
(0)
5
4
2
3
(0)
(0)
(0)
(0)
Function
2
1
0
RDR0
(0)
(0)
1
0
RDR1
(0)
(0)
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