PSD835G2 View Datasheet(PDF) - STMicroelectronics
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PSD835G2 Datasheet PDF : 110 Pages
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PSD835G2
The
PSD835G2
Functional
Blocks
(cont.)
PSD8XX Family
9.3 Microcontroller Bus Interface
The “no-glue logic” PSD835G2 Microcontroller Bus Interface can be directly connected to
most popular microcontrollers and their control signals. Key 8-bit microcontrollers with their
bus types and control signals are shown in Table 14. The MCU interface type is
specified using the PSDsoft.
Table 14. Microcontrollers and their Control Signals
Data
Bus
MCU
Width CNTL0 CNTL1 CNTL2 PC7 PD0**
8031/8051 8
WR RD
PSEN
* ALE
80C51XA
8
WR RD
PSEN
* ALE
80C251
8 WR PSEN
*
* ALE
80C251
8
WR RD
PSEN
* ALE
80198
8 WR RD
*
* ALE
68HC11
8 R/W E
*
* AS
68HC05C0 8 WR RD
*
* AS
68HC912 8 R/W E
*
DBE AS
Z80
8 WR RD
*
**
Z8
8 R/W DS
*
* AS
68330
8 R/W DS
*
* AS
M37702M2 8 R/W E
*
* ALE
ADIO0
A0
A4
A0
A0
A0
A0
A0
A0
A0
A0
A0
A0
PF3-PF0 PF7-PF4
*
*
A3-A0
*
*
*
*
*
*
*
*
*
*
*
*
*
D3-D0 D7-D4
*
*
*
*
D3-D0 D7-D4
**Unused CNTL2 pin can be configured as PLD input. Other unused pins (PD3-0, PA3-0) can be
**configured for other I/O functions.
**ALE/AS input is optional for microcontrollers with a non-multiplexed bus
9.3.1. PSD835G2 Interface to a Multiplexed Bus
Figure 17 shows an example of a system using a microcontroller with a 8-bit multiplexed
bus and a PSD835G2. The ADIO port on the PSD835G2 is connected directly to the
microcontroller address/data bus. ALE latches the address lines internally. Latched
addresses can be brought out to Port E, F or G. The PSD835G2 drives the ADIO data bus
only when one of its internal resources is accessed and the RD input is active. Should the
system address bus exceed sixteen bits, Ports A, B, C, or F may be used as additional
address inputs.
9.3.2. PSD835G2 Interface to a Non-Multiplexed Bus
Figure 18 shows an example of a system using a microcontroller with a 8-bit
non-multiplexed bus and a PSD835G2. The address bus is connected to the ADIO Port,
and the data bus is connected to Port F. Port F is in tri-state mode when the PSD835G2
is not accessed by the microcontroller. Should the system address bus exceed sixteen
bits, Ports A, B or C may be used for additional address inputs.
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