psd813f1a STMicroelectronics, psd813f1a Datasheet - Page 54

• Manufacturer Part Number: psd813f1a
• Description: Flash In-system Programmable Isp Peripherals For 8-bit Mcus, 5 V
• Manufacturer: STMicroelectronics

PSD813F1A
MCU I/O Mode
In the MCU I/O Mode, the microcontroller uses the
PSD ports to expand its own I/O ports. By setting
up the CSIOP space, the ports on the PSD are
mapped into the microcontroller address space.
The addresses of the ports are listed in
6., page
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
Mode, page
output, the content of the Data Out Register drives
the pin. When configured as an input, the micro-
controller can read the port input through the Data
In buffer. See
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 equation 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, and/or as an output from
the CPLD’s Output Macrocells. The output can be
tri-stated with a control signal. This output enable
control signal can be defined by a product term
Table 19. Port Operating Modes
Note: 1. Can be multiplexed with other I/O functions.
54/111
MCU I/O
PLD I/O
McellAB Outputs
McellBC Outputs
Additional Ext. CS Outputs
PLD Inputs
Address Out
Address In
Data Port
Peripheral I/O
JTAG ISP
the
Port Mode
17.
56. When the pin is configured as an
section
Figure 27., page
entitled
Yes
Yes
No
No
Yes
Yes (A7-A0
Yes
Yes (D7-D0)
Yes
No
53.
Port A
Peripheral
Table
Yes
Yes
Yes
No
Yes
Yes (A7-A0)
or (A15-A8)
Yes
No
No
No
I/O
Port B
from the PLD, or by setting 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 as a PLD input pin in PSDabel.
The PLD I/O Mode is specified in PSDabel by de-
claring the port pins, and then writing an equation
assigning the PLD I/O to a port.
Address Out Mode
For microcontrollers with a multiplexed address/
data bus, Address Out Mode can be used to drive
latched addresses onto the port pins. These port
pins can, in turn, drive external devices. Either the
output enable or the corresponding bits of both the
Direction 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
21., page 55
ments on Ports A and B for various MCUs.
For non-multiplexed 8-bit bus mode, address lines
A7-A0 are available to Port B in Address Out
Mode.
Note: do not drive address lines with Address Out
Mode to an external memory device if it is intended
for the MCU to boot from the external device. The
MCU must first boot from PSD memory so the Di-
rection and Control register bits can be set.
Yes
No
Yes
No
Yes
No
Yes
No
No
Yes
for the address output pin assign-
1
Port C
Yes
No
No
Yes
Yes
No
Yes
No
No
No
Port D
Table