psd4235g2 STMicroelectronics, psd4235g2 Datasheet - Page 81

• Manufacturer Part Number: psd4235g2
• Description: Flash In-system Programmable Isp Peripherals For 16-bit Mcus 5v Supply
• Manufacturer: STMicroelectronics

PSD4235G2
20.2
Figure 26. General I/O port architecture
ADDRESS
ALE
Port operating modes
The I/O Ports have several modes of operation. Some modes can be defined using PSDsoft
Express, some by the MCU writing to the registers in CSIOP space, and some by both. The
modes that can only be defined using PSDsoft Express must be programmed into the
device and cannot be changed unless the device is reprogrammed. The modes that can be
changed by the MCU can be done so dynamically at run-time. The PLD I/O, Data Port,
Address input, Peripheral I/O and MCU Reset modes are the only modes that must be
defined before programming the device. All other modes can be changed by the MCU at
run-time. See Application Note AN1171 for more detail.
Table 39
where the different modes are configured. Each of the port operating modes are described
in the following sections.
MACROCELL OUTPUTS
EXT CS
WR
ENABLE PRODUCT TERM ( .OE )
WR
WR
summarizes which modes are available on each port.
CONTROL REG.
CPLD -INPUT
DATA OUT
READ MUX
DIR REG.
D
D
G
D
D
REG.
D
B
P
Q
Q
Q
Q
DATA IN
DATA OUT
ADDRESS
OUTPUT
OUTPUT
SELECT
MUX
ENABLE OUT
Table 40
MACROCELL
INPUT
shows how and
I/O ports
PORT PIN
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