TMS320F243, TMS320F241
DSP CONTROLLERS
SPRS064B – DECEMBER 1997 – REVISED FEBRUARY 1999
9
POST OFFICE BOX 1443
HOUSTON, TEXAS 77251–1443
Terminal Functions - ’F243 PGE Package (Continued)
NAME
144
QFP
NO.
TYPE
RESET
STATE
DESCRIPTION
INTERRUPT, EXTERNAL ACCESS, AND MISCELLANEOUS SIGNALS (CONTINUED)
I/O, data, and program space strobe select signals. IS, DS, and PS are always high
t d f
110
O/Z
1
They are placed in the high-impedance state during reset, power down, and when
107
EMU1/OFF is active low.
IS
DS
PS
105
t th
unless low-level asserted for access to the relevant external memory space or I/O.
They are laced in the high-im edance state during reset, ower down, and when
WE
112
O/Z
1
Write enable strobe. The falling edge of WE indicates that the device is driving the
external data bus (D15–D0). WE is active on all external program, data, and I/O
writes. WE goes in the high-impedance state when EMU1/OFF is active low.
RD
118
O
1
Read enable strobe. Read-select indicates an active, external read cycle. RD is
active on all external program, data, and I/O reads. RD goes into the
high-impedance state when EMU1/OFF is active low.
R/W
114
O/Z
1
Read/write signal. R/W indicates transfer direction during communication to an
external device. It is normally in read mode (high), unless low level is asserted for
performing a write operation. It is placed in the high-impedance state when
EMU1/OFF is active low and during power down.
STRB
122
O/Z
1
External memory access strobe. STRB is always high unless asserted low to
indicate an external bus cycle. STRB is active for all off-chip accesses. It is placed
in the high-impedance state during power down, and when EMU1/OFF is active
low.
BR
120
O/Z
1
Bus request, global memory strobe. BR is asserted during access of
external global data memory space. BR can be used to extend the data memory
address space by up to 32K words. BR goes in the high-impedance state during
reset, power down, and when EMU1/OFF is active low.
VIS_CLK
31
O
0
Visibility clock. Same as CLKOUT, but timing is aligned for external buses in
visibility mode.
ENA_144
18
I
I
Active high to enable external interface signals. If pulled low, the ’F243 behaves like
an ’F241—i.e., it has no external memory and generates an illegal address if any
of the three external spaces are accessed (IS, DS, PS asserted). This pin has an
internal pulldown.
VIS_OE
126
O
0
This pin is active (low) whenever the external databus is driving as an output during
visibility mode. Can be used by external decode logic to prevent data bus
contention while running in visibility mode.
XF
/IOPC0
49
I/O
O – 1
External flag output (latched software-programmable signal). XF is a
general-purpose output pin. It is set/reset by the
SETC XF/CLRC XF
instruction.
This pin is configured as an external flag output by all device resets. It can be used
as a GPIO, if not used as XF.
BIO
/IOPC1
55
I/O
I
Branch control input. BIO is polled by the
BCND pma,BIO
instruction. If BIO is low,
a branch is executed. If BIO is not used, it should be pulled high. This pin is
configured as a branch control input by all device resets. It can be used as a GPIO,
if not used as a branch control input.
I = input, O = output, Z = high impedance
The reset state indicates the state of the pin at reset. If the pin is an input, indicated by an I, its state is determined by user design. If the pin is
an output, its level at reset is indicated.
§ In silicon revisions 2.0-TMX and 2.1-TMS, this pin is level-sensitive and can cause multiple interrupts when held low.
Data is in output mode when AVIS is enabled. At reset, the device comes up with AVIS mode enabled. The data bus is in output mode while AVIS
is enabled.
NOTE:
Bold, italicized pin names
indicate pin function after reset.