Parallel Interface Modes - Profichip VPC3+S User Manual

8 Hardware Interface
8.1.2

Parallel Interface Modes

The Bus Interface Unit (BIU) is the interface to the connected
processor/microcontroller. This is a synchronous or asynchronous 8-bit
interface with an 11-bit (12-bit in 4K Byte mode) address bus. The interface
is configurable via 2 pins (XINT/MOT, MODE). The connected processor
family (bus control signals such as XWR, XRD, or R_W and the data
format) is specified with the XINT/MOT pin. Synchronous or asynchronous
bus timing is specified with the MODE pin.
SERMODE
Figure 8-1: Configuration of the parallel Processor Interface Modes
Examples of various Intel system configurations are given in subsequent
sections. The internal address latch and the integrated decoder must be
used in the synchronous Intel mode. One figure shows the minimum con-
figuration of a system with the VPC3+S, where the chip is connected to an
EPROM version of the controller. Only a clock generator is necessary as an
additional device in this configuration. If a controller is to be used without an
integrated program memory, the addresses must be latched for the external
memory.
Notes:
If the VPC3+S is connected to an 80286 or similar processor, it must be
taken into consideration that the processor carries out word accesses. That
is, either a 'swapper' is necessary that switches the characters out of the
VPC3+S at the correct byte position of the 16-bit data bus during reading or
the least significant address bit is not connected and the 80286 must read
word accesses and evaluate only the lower byte.
88
XINT/MOT
0 0
0 0
0 1
0 1
Revision 1.04
MODE Processor Interface Mode
1 Synchronous Intel mode
0 Asynchronous Intel mode
0 Asynchronous Motorola mode
1 Synchronous Motorola mode
VPC3+S User Manual
Copyright © profichip GmbH, 2012