SMC Networks Sharp ARM720T_LH79520 - Manual (Page 8)

ARM720T_LH79520 – Sharp LH79520 SoC with ARM720T 32-bit RISC Processor
Name Type Polarity/Bus size Description
PER_RESET
I Low
Reset signal from the LH79520.
ARM7_SYS_RESE
T
O Low
Reset signal to the LH79520 (internally connected from the RST_I
line).
PER_CLK
I Rise
Clock signal from the LH79520
ARM7_SYS_CLK
O Rise
External Clock signal to the LH79520 (internally connected from the
CLK_I line).
PER_READY
O Low
Static Memory Controller External Wait Control
PER_INT
O 5/High
External Interrupt lines. These lines appear as interrupts 0 to 4 when
handled by the physical device's Vectored Interrupt Controller (see
Interrupts ).
Configuring the Processor
The architecture of the ARM720T_LH79520 can be configured after placement on the schematic sheet, or OpenBus System
document, using the Configure (32-bit Processors) dialog (Figure 2). Access to this dialog depends on the document in which
you are working:
• In the Schematic document – simply right-click over the device and choose the command to configure the processor from
the context menu that appears. Alternatively, click on the Configure button, available in the Component Properties dialog for
the device.
• In the OpenBus System document – access the dialog by right-clicking over the component and choosing the command to
configure the processor from the menu that appears. Alternatively, double-click on the component to access the dialog
directly.
Figure 2. Options to configure the architecture of the ARM720T_LH79520.
The drop-down field at the top-right of the dialog enables you to choose the type of processor you want to work with. As the
pinouts for the Wishbone interfaces between the 32-bit processors are the same, you can easily change the processor used in
your design without having to extensively rewire the external interfaces.
As you select the processor type, the Configure (32-bit Processors) dialog will change accordingly to reflect the architectural
options available. The symbol on the schematic will also change to reflect the type of processor and configuration options
chosen.
For the ARM720T_LH79520, a single architectural option is available that allows you to define the size of the internal memory
for the processor. This memory, also referred to as ‘Low’ or ‘Boot’ memory is implemented using true dual port FPGA Block
RAM and will contain the boot part of a software application and the interrupt and exception handlers.
8 CR0162 (v2.0) March 10, 2008