TMS320VC5501 Datasheet, PDF (45/193 Pages) Texas Instruments – TMS320VC5501 Fixed-Point Digital Signal Processor

Functional Overview
3.3.2 Host Port Mux
The 5501 Host Port Mux controls the function of 8 data signals (pins HD[7:0]) and 2 control signals (pins HC0
and HC1). The Host Port Mux supports two different modes:
• 8-bit multiplexed mode: The HPI’s 8 data and 2 control signals are routed to their corresponding pins
on the Host Port Mux.
• Parallel general-purpose I/O mode: All pins on the Host Port Mux are routed to PGPIO. The HPI and
EMIF are disabled.
The mode of the Host Port Mux is determined by the state of the GPIO6 pin at reset. If GPIO6 is low, the pins
of the Host Port Mux will be set to PGPIO. In this mode, the EMIF and the HPI will be disabled. The
Parallel/Host Port Mux Mode bit of the External Bus Control Register will be set to 0 to reflect the PGPIO mode
of the Host Port Mux.
If GPIO6 is high, the HPI will be enabled in 8-bit (multiplexed) mode: pins HD[7:0] are set to HPI.HD[7:0], and
HC0 and HC1 are set to HPI.HAS and HPI.HBIL, respectively. The Parallel/Host Port Mux Mode bit field in
the XBSR will be set to 1 to reflect the HPI multiplexed mode of the Host Port Mux. See Section 3.7, Host-Port
Interface (HPI), for more information on the operation of the HPI in multiplexed mode.
Table 3−5 lists the individual routing of the HPI and PGPIO signals to the Host Port Mux pins.
Table 3−5. TMS320VC5501 Routing of Host Port Mux Signals
PIN
HD[7:0]
HC0
HC1
PARALLEL/HOST PORT MUX MODE = 0
(PGPIO)
Data Bus
PGPIO[43:36]
Control Bus
PGPIO44
PGPIO45
PARALLEL/HOST PORT MUX MODE = 1
(8-BIT HPI MULTIPLEXED)
HPI.HD[7:0]
HPI.HAS
HPI.HBIL
December 2002 − Revised November 2004
SPRS206H
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