PSD813F2V Datasheet, PDF (53/110 Pages) STMicroelectronics – Flash In-System Programmable (ISP) Peripherals for8-bits MCUs, 3V

PSD813F2V, PSD833F2V, PSD853F2V, PSD854F2V
MCU I/O Mode
In the MCU I/O mode, the MCU uses the I/O Ports
block to expand its own I/O ports. By setting up the
CSIOP space, the ports on the PSD are mapped
into the MCU address space. The addresses of
the ports are listed in Table 7., page 18.
A port pin can be put into MCU I/O mode by writing
a 0 to the corresponding bit in the Control Regis-
ter. The MCU I/O direction may be changed by
writing to the corresponding bit in the Direction
Register, or by the output enable product term.
See the section entitled Peripheral I/O
Mode, page 55. When the pin is configured as an
output, the content of the Data Out Register drives
the pin. When configured as an input, the MCU
can read the port input through the Data In buffer.
See Figure 26., page 52.
Ports C and D do not have Control Registers, and
are in MCU I/O mode by default. They can be used
for PLD I/O if equations are written for them in PS-
Dabel.
PLD I/O Mode
The PLD I/O Mode uses a port as an input to the
CPLD’s Input Macrocells (IMC), and/or as an out-
put from the CPLD’s Output Macrocells (OMC).
The output can be tri-stated with a control signal.
This output enable control signal can be defined
by a product term from the PLD, or by resetting the
corresponding bit in the Direction Register to ’0.’
The corresponding bit in the Direction Register
must not be set to '1' if the pin is defined for a PLD
input signal in PSDabel. The PLD I/O mode is
specified in PSDabel by declaring the port pins,
and then writing an equation assigning the PLD I/
O to a port.
Address Out Mode
For MCUs with a multiplexed address/data bus,
Address Out Mode can be used to drive latched
addresses on to the port pins. These port pins can,
in turn, drive external devices. Either the output
enable or the corresponding bits of both the Direc-
tion Register and Control Register must be set to
a 1 for pins to use Address Out Mode. This must
be done by the MCU at run-time. See Table 21 for
the address output pin assignments on Ports A
and B for various MCUs.
For non-multiplexed 8-bit bus mode, address sig-
nals (A7-A0) are available to Port B in Address Out
Mode.
Note: Do not drive address signals with Address
Out Mode to an external memory device if it is in-
tended for the MCU to Boot from the external de-
vice. The MCU must first Boot from PSD memory
so the Direction and Control register bits can be
set.
Table 19. Port Operating Modes
Port Mode
Port A
MCU I/O
Yes
PLD I/O
McellAB Outputs
Yes
McellBC Outputs
No
Additional Ext. CS Outputs No
PLD Inputs
Yes
Address Out
Yes (A7 – 0)
Address In
Yes
Data Port
Yes (D7 – 0)
Peripheral I/O
Yes
JTAG ISP
No
Note: 1. Can be multiplexed with other I/O functions.
Port B
Yes
Yes
Yes
No
Yes
Yes (A7 – 0)
or (A15 – 8)
Yes
No
No
No
Port C
Yes
No
Yes
No
Yes
No
Yes
No
No
Yes¹
Port D
Yes
No
No
Yes
Yes
No
Yes
No
No
No
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