Lattice Semiconductor LatticeMico32, Hardware Developer User Manual

Page: 64 / 133

C
REATING
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USTOM
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OMPONENTS IN
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ATTICE
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ICO
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YSTEM
: Specifying WISHBONE Interface Connections
58
LatticeMico32 Hardware Developer User Guide
Table 2 lists the options available in the Master/Slave Ports tab of the Import/
Create Custom Component dialog box.
Table 2: Master/Slave Port Tab Options
Option Description
Master/Slave Ports Lists the master ports and the slave ports in your component.

You can create more than one master port.

You can create only one slave port.
Delete To delete a master port or a slave port, highlight the port in the Master/Slave
Ports list and click
Delete .
The port is not permanently deleted until you
save the component by using the Save or OK button.
Note : You cannot “undo” a port deletion. Once you click Delete and then OK, the
port is permanently deleted.
Type Specifies the type of port. Choose either MasterPort or SlavePort in the drop-
down menu.
Master ports can generate WISHBONE cycles to attached
WISHBONE slave components. Slave ports cannot initiate WISHBONE
bus cycles; they can only respond to a WISHBONE master.
Display Name Specifies the name of the master or slave port. The name is displayed indented
and below the
instance name of a component that has been added to a
MSB platform
. Any ASCII character is permitted in this field.
Prefix Specifies a prefix that is used for two purposes:

It creates a unique name for the component ports connected to the
WISHBONE bus, for example, <
prefix >_DAT_O.

It enables you to use the same instance name for different components and
avoid having name conflicts in the wires of the platform’s top level. When the
top-level interconnect is built, the wire connecting a slave component output
back to the master or masters is named
<
instance_name >< component_port_name >. Since < prefix > is used in
< component_port_name >, < prefix > appears in this wire name. For example,
if the prefix for a GPIO component is “GPIO,” the wire name will be
inst1GPIO_DAT_O.
Port Attributes
The Port Attributes group box is used to perform a name translation
between the WISHBONE signal names in your custom component and
the WISHBONE signal names attached to the LatticeMico32 bus arbiter.
Refer to Table 3 on page 59 for a description of WISHBONE slave port signals.
Update Updates the options in the Master/Slave Ports tab.
The Update button is only
available after a master or slave port entry in the Master/Slave Ports
group box has been highlighted. The Port Attributes group box displays
the values associated with the highlighted master or slave port element.
Use the Update button after modifying any of the Port Attribute fields.
Add Adds the master port or slave port to the Master/Slave Ports list at the top of the
dialog box.
Reset Clears the port attributes.
DRC Performs a design-rule check of the new component.