PSD4235G2-12UIT STMICROELECTRONICS [STMicroelectronics], PSD4235G2-12UIT Datasheet - Page 66

• Manufacturer Part Number: PSD4235G2-12UIT
• Description: Flash in-system programmable (ISP) peripherals for 16-bit MCUs (3.3 V supply)
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

MCU bus interface
18.2
Figure 19. An example of a typical 16-bit non-multiplexed bus interface
18.3
66/124
RESET
MCU
PSD interface to a non-multiplexed 8-bit bus
Figure 19
and a PSD4235G2V. The address bus is connected to the ADIO Port, and the data bus is
connected to Ports F and G. Ports F and G are in tri-state mode when the PSD is not
accessed by the MCU. Should the system address bus exceed sixteen bits, Ports A, B, or C
may be used for additional address inputs.
Data Byte Enable reference
MCUs have different data byte orientations.
PSD4235G2V interprets byte/word operations in different bus write configurations. Even-
byte refers to locations with address A0 equal to '0,' and odd byte as locations with A0 equal
to '1.'
Table 34.
BHE
BHE
ALE
WR
0
0
1
RD
shows an example of a system using a MCU with a 16-bit non-multiplexed bus
16-bit data bus with BHE
D [ 15:0 ]
A [ 15:0 ]
A0
0
1
0
Odd Byte
Odd Byte
—
PSD
WR ( CNTRL0 )
RD ( CNTRL1 )
BHE ( CNTRL2 )
RST
ALE ( PD0 )
PORT D
PORT
ADIO
D15-D8
Table 34
PORT
PORT
PORT
A, B
or C
to
G
F
Table 37
Even Byte
—
Even Byte
show how the
( OPTIONAL )
D[15:8]
D [ 7:0 ]
A [ 23:16 ]
D7-D0
PSD4235G2V
AI04929