Jameco Electronics 3000, 2000 manual Rabbit Slave Port, SD0-SD7

Models: 3000 2000

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13.RABBIT SLAVE PORT

13.RABBIT SLAVE PORT

When a Rabbit microprocessor is configured as a slave, Parallel Port A and certain other data lines are used as communication lines between the slave and the master. The slave unit is a Rabbit configured as a slave. The master can be another Rabbit or any other type of processor. Rabbits configured as slaves can themselves have slaves.

The master and slave communicate with each other via the slave port. The slave port is a physical device that includes data registers, a data bus and various handshaking lines. The slave port is a part of the slave Rabbit, but logically it is an independent device that is used to communicate between the two processors. A diagram of the slave port is shown in Figure 13-1.

 

 

SPSR

81-88

 

SPD2R

SD0-SD7

 

98

 

SA1

SPD1R

97

SA0

 

95

 

/SWR

SPD0R

96

/SRD

 

21

 

/SCS

CPU

 

100

/SLAVEATTN

 

Figure 13-1. Rabbit Slave Port

The slave port has three data registers for each direction of communication. Three regis- ters, named SPD0R, SPD1R, and SPD2R, can be written by the master and read by the slave. Three different registers, also named SPD0R, SPD1R, and SPD2R, can be written by the slave and read by the master. The same names are used for different registers since it is usually clear from the context which register is meant. If it is necessary to distinguish between registers, we will refer to the registers as “SPD0R writable by the slave” or “SPD0R writable by the master.”

User’s Manual

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Jameco Electronics 3000, 2000 manual Rabbit Slave Port, SD0-SD7