Zilog EZ80F91 - Manual (Page 47)

eZ80F91 Development Kit
User Manual
UM014220-0508 eZ80F91 Module
42
eZ80F91 Module
This section describes the eZ80F91 Module hardware, its interfaces and
key components, including the CPU, real-time clock, IrDA transceiver,
and memory.
Functional Description
The eZ80F91 Module is a compact, high-performance module specially
designed for the rapid development and deployment of embedded sys-
tems. Additional devices such as serial ports, LED matrices, GPIO ports,
and I
2
C devices are supported when connected to the eZ80Acclaim!
®
Development Kit. A block diagram representing both of these boards is
shown in
Figure 1 on page 4.
Despite its small footprint, the eZ80F91 Module provides a CPU, Flash
memory, Ethernet interface, SRAM, an IrDA transceiver, and a real-time
clock with a back-up battery. This module is powered by the eZ80F91
microcontroller, a new member of eZ80
®
product family. The eZ80F91
Module can also be used as a stand-alone development tool when pro-
vided with an external power source.
The eZ80F91 Module is equipped with an Am79C874 PHY from AMD.
This PHY supports a number of different frequencies and types of com-
munication, from 10 MB half-duplex to 100 MB full-duplex. There are
four resistors on the Module that control settings for the requested mode
of operation; these resistors are labelled R19, R21, R23, and R24. For
details, refer to eZ80F91 Module Product Specification (PS0193).
Fast Buffer
A Fast Buffer is located on the data bus to Flash memory. The purpose of
this Fast Buffer is to avoid bus contention that can exist due to the slow
turn-off time of Flash memory and the fast bus turn-around time of the