20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 175

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

These connections are summarized in Table 18-3.
Note that the slave port on the master Rabbit processor is not used; the master uses the
data bus to send and receive data to the slave port data registers on the slave devices.
In this setup, pins PD6 and PD7 are set up as I/O strobe chip selects for the two slave
devices, and PE0 and PE1 are used as external interrupt inputs to monitor the /SLVATTN
signals from the slaves.
In this setup, the slave port is used as follows:
• The slave responds to the interrupt and reads the slave port data registers.
• When the slave wishes to send data to the master, it writes the slave port data registers,
• When the master detects the change on /SLVATTN, it reads the slave port data registers.
18.3.1 Master Setup
1. Enable the I/O strobes on PD6 and PD7 by writing to the appropriate Parallel Port D
2. Enable the external interrupts on PE0 and PE1 by writing to the appropriate external
18.3.2 Slave Setup
1. Write the vector to the interrupt service routine to the internal interrupt table.
2. Configure SPCR to select the interrupt priority (note that interrupts will be enabled
Chapter 18 Slave Port
writing SPD0R last, which enables the /SLVATTN signal.
pin and external I/O registers.
interrupt registers.
once this value is set).
Data Bus
Address Bus
I/O Read Strobe
I/O Write Strobe
Slave #1 Chip Select
(I/O strobe I6)
Slave #2 Chip Select
(I/O strobe I7)
External Interrupt 0
(from Slave #1)
External Interrupt 1
(from Slave #2)
Master
Table 18-3. Typical Slave Port Connections
D0–D7
A0–A1
/IOWR
/IORD
PD6
PD7
PE0
PE1
/SLVATTN
SD0–SD7
SA0–SA1
/SWR
/SRD
/SCS
—
—
Slave #1
PB4–PB5
PA0–PA7
PB3
PB2
PB6
PB7
—
—
/SLVATTN
SD0–SD7
SA0–SA1
/SWR
/SRD
/SCS
—
–
Slave #2
PA0–PA7
PB4–PB5
PB3
PB2
PB6
PB7
—
—
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