psd311-b-90ui STMicroelectronics, psd311-b-90ui Datasheet - Page 29

• Manufacturer Part Number: psd311-b-90ui
• Description: Low Cost Field Programmable Microcontroller Peripherals
• Manufacturer: STMicroelectronics

13.0
Program/Data
Space and the
8031
26
PSD3XX Family
Figure 9. Combined Address Space
Figure 10. 8031-Compatible Separate Code and Data Address Spaces
This section only applies to users who have an 8031 or compatible MCU that outputs a
signal such as PSEN when accessing program space. If this applies to you, be aware of the
following:
The PSD3XX can be configured using PSDsoft such that the EPROM is either
1) accessed by PSEN only (Figure 10); or 2) accessed by PSEN or RD (Figure 9).
The default is PSEN only unless changed in PSDsoft.
The SRAM and I/O Ports (including CSIOPORT) can not be placed in program space
only. By default, they are in data space only (Figure 10). However, the SRAM may
be placed in Program and Data Space, as shown in Figure 9.
*
*
Not available on “R” versions.
Not available on “R” versions.
INTERNAL
ADDRESS
PSEN
INTERNAL
ADDRESS
PSEN
RD
RD
OE
I/O PORTS
I/O PORTS
PAD
PAD
CS
CS
OE
CS
OE
CS
CS
CS
OE
EPROM
EPROM
OE
SRAM
SRAM
OE
*
*