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Rabbit 3000 Microprocessor User’s Manual
13.4 Register Descriptions
Parallel Port F Data Register
(PFDR)
(Address = 0x0038)
Bit(s)
Value
Description
7:0
Read
The current state of Parallel Port F pins PF7–PF0 is reported.
Write
The Parallel Port F preload register is written with this value for transfer to the
Parallel Port F output register on the next rising edge of the peripheral clock.
Parallel Port F Control Register
(PFCR)
(Address = 0x003C)
Bit(s)
Value
Description
7:6
00
These bits are ignored and should be written with zero.
5:4
00
The upper nibble peripheral clock is perclk/2.
01
The upper nibble peripheral clock is the output of Timer A1.
10
The upper nibble peripheral clock is the output of Timer B1.
11
The upper nibble peripheral clock is the output of Timer B2.
3:2
00
These bits are ignored and should be written with zero.
1:0
00
The lower nibble peripheral clock is perclk/2.
01
The lower nibble peripheral clock is the output of Timer A1.
10
The lower nibble peripheral clock is the output of Timer B1.
11
The lower nibble peripheral clock is the output of Timer B2.
Parallel Port F Function Register
(PFFR)
(Address = 0x003D)
Bit(s)
Value
Description
7:4
0
The corresponding port bit is a parallel port I/O pin.
1
The corresponding port bit is a PWM output (PWM3–PWM0).
3:2
0
The corresponding port bit is a parallel port I/O pin.
1
The corresponding port bit is a Quadrature Decoder input (QD2A–QD2B).
(This value was not used for the Rabbit 3000 chip.).
1:0
0
The corresponding port bit is a parallel port I/O pin.
1
The corresponding pin pair enables the clock ouputs for Serial Ports C and D
when the serial port is configured for internal clock generation or is a Quadrature
Decoder input (QD1A–QD1B).