Sundance SMT310Q - Manual (Page 23)

Version 2.1 Page 23 of 55 SMT310Q User Manual
7. Global/Local Bus Transfers, DSP ↔ PCI.
The traditional global bus interface on C6x DSP modules interfaces to the SMT310Q
via a local bus. This allows Global bus transfers on the DSP to be converted into
local bus accesses, giving direct DSP accesses to the PCI bridge chip.
The resources in the PCI bridge chip are illustrated in the figure below.
PCI Bridge Device
MailBox
Read/Write
Interrupt Control
Local To PCI Bus
Apperture Control
LOCAL <-> PCI
Apperture 0
16MB Address
Space
DSP Global
Bus Access
Arbitration
Unit
Local Bus
Figure 7: Local Bus to DSP Connectivity
7.1
Mailbox Accesses
The mailbox registers can be used to transfer commands or small amounts of
data between the PCI bus and the DSP, via the local bus. The PCI bridge
device provides 16 8-bit mailbox registers, which may be used to communicate
data between the DSP and Host.
The mailbox registers are accessed from the DSP through the Local-to-Internal
Register (LB_IO_BASE) aperture. As illustrated in section 5, table 4 of this
document, this region is accessed by the DSP via a global bus access to the
PCI Bridge Registers (Address: 1C000000
16
).