PSD4235G2V-10U STMICROELECTRONICS [STMicroelectronics], PSD4235G2V-10U Datasheet - Page 65

• Manufacturer Part Number: PSD4235G2V-10U
• Description: Flash In-System Programmable (ISP) Peripherals for 16-bit MCUs
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Port Data Registers
The Port Data Registers, shown in Table 47, are
used by the MCU to write data to or read data from
the ports. Table 47 shows the register name, the
ports having each register type, and MCU access
for each register type. The registers are described
next.
Data In
Port pins are connected directly to the Data In buff-
er. In MCU I/O Input mode, the pin input is read
through the Data In buffer.
Data Out Register
Stores output data written by the MCU in the MCU
I/O Output mode. The contents of the Register are
driven out to the pins if the Direction Register or
the output enable product term is set to 1. The
contents of the register can also be read back by
the MCU.
Table 47. Port Data Registers
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
Data In
Data Out
Output Macrocell
Mask Macrocell
Input Macrocell
Enable Out
Register Name
A, B, C, D, E, F,
G
A, B, C, D, E, F,
G
A, B
A, B
A, B, C
A, B, C, F
Port
READ – input on pin
WRITE/READ
READ – outputs of Macrocells
WRITE – loading Macrocells Flip-flop
WRITE/READ – prevents loading into a given
Macrocell
READ – outputs of the Input Macrocells
READ – the output enable control of the port driver
Output Macrocells (OMC)
The CPLD Output Macrocells (OMC) occupy a lo-
cation in the MCU’s address space. The MCU can
read the output of the Output Macrocells (OMC). If
the Mask Macrocell Register bits are not set, writ-
ing to the Macrocell loads data to the Macrocell
flip-flops. See the section entitled “I/O PORTS”, on
page 58.
Mask Macrocell Register
Each Mask Macrocell Register bit corresponds to
an Output Macrocell (OMC) flip-flop. When the
Mask Macrocell Register bit is set to a 1, loading
data into the Output Macrocell (OMC) flip-flop is
blocked. The default value is 0, or unblocked.
Input Macrocells (IMC)
The Input Macrocells (IMC) can be used to latch or
store external inputs. The outputs of the Input
Macrocells (IMC) are routed to the PLD input bus,
and can be read by the MCU. See the section en-
titled “Input Macrocells (IMC)”, on page 45.
MCU Access
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