User`s manual

User’s Manual 27
As shown in Table 2, pins PA0–PA7 can be used to allow the Rabbit 2000 to be a slave to
another processor. PE0, PE1, PE4, and PE5 can be used as external interrupts INT0A,
INT1A, INT0B, and INT1B. Pins PB0 and PB1 can be used to access the clock on Serial
Port B and Serial Port A of the Rabbit microprocessor. Pins PD4 and PD6 can be pro-
grammed to be optional serial outputs for Serial Ports B and A. PD5 and PD7 can be used
as alternate serial inputs by Serial Ports B and A.
4.1.1 Dedicated Inputs
PB0 and PB1 are designated as inputs because the Rabbit 2000 is operating in an asyn-
chronous mode. Four of the input-only pins are located on PB2–PB5. When Port C is
used
as a parallel port, PC1, PC3, PC5, and PC7 are also inputs only. All the inputs are pulled up
with 47 k Ω resistors. Figure 6 shows the locations of these pullup resistors.
Figure 6. Locations of Digital Input Pullup Resistors
NOTE: All the digital input pullup resistors are located on the bottom side of RCM2000
boards marked 175-0168
PB2–PB5 can instead be used for the slave port. PB2 and PB3 are slave write and slave
read strobes, while PB4 and PB5 serve as slave address lines SA0 and SA1, and are used
to access the slave registers (SD0–SD7), which is the alternate assignment for Parallel
Port A. Parallel Port C pins PC1, PC3, PC5, and PC7 are inputs only can alternately be
selectively enabled to serve as the serial data inputs for Serial Ports D, C, B, and A.
4.1.2 Dedicated Outputs
Two of the output-only pins are located on PB6–PB7. PB7 can also be used with the slave
port as the /SLAVEATTN output. This configuration signifies that the slave is requesting
attention from the master. When Port C is used as a parallel port, PC0, PC2, PC4 and PC6
are outputs only. These pins can alternately serve as the serial data outputs for Serial Ports
D, C, B, and A.
J1
U11
C18
R37
R38
R40
R41
R42
R39
R14
C12
C13
R3
R15
R28
C3
Q14
R5
Q11Q10
R16
JP2
D1
C15
R36
C6
R34
R35
U10
R27
U1
U2
R4
Y1
C1
C2
R2
R1
JP1
TP3
TP2
J3
PB5
PB7
GND
PB4
PB6
PCLK
D6
D7
D2
D3
D5
D4
D1
D0
PE7
PE6
PE5
PE4
PE3
PE2
PE1
PE0
/IOW
/IOR
/BEN
/WDO
PA1
PA3
PA5
PA7
PB1
PB3
GND
PA0
PA2
PA4
PA6
PB0
PB2
J1
VCC
J2
A12
A10
A8
A6
A4
A2
A0
A11
A9
A7
A5
A3
A1
STAT
PC0
PC2
PC4
PC6
PD0
PD2
PD4
PD6
GND
VBAT
PC1
PC3
PC5
PC7
PD1
PD3
PD5
PD7
VCC
SM1
GND
VRAM
SM0
VCC
/RESO
/RSTI
SRAM
JP3
TP1
C7
D3
R11
U5
R6
R8
D2
R7
C8
C9
TP4
Top Side
R21
R22
R23
R24
R25
R26
Parallel Port B
Input Pullup Resistors
{
Q13
A12
A6
A4
A2
A0
PC0
PC2
PC4
PC6
PD0
PD2
PD4
PD6
GND
VBAT
SM0
/RESO
VCC
A10
A8
GND
/RSTI
SM1
VRAM
VCC
PD7
PD5
PD3
PD1
PC7
PC5
PC3
PC1
STAT
A1
A3
A5
A7
A9
A11
VCC
PA1
PA3
PA5
PA7
PB1
PB3
PB5
PB7
GND
D6
D4
D2
D0
/WDO
/IOR
PE0
PE2
PE4
PE6
/BEN
/IOW
PE1
PE3
PE5
PE7
D1
D3
D5
D7
PCLK
PB6
PB4
PB2
PB0
PA6
PA4
PA2
PA0
GND
Bottom Side
C10
C11
C16
R9
RT1
R12
C19
175-0201
Flash
EPROM
Parallel Port C
Input Pullup Resistors