80C32 Datasheet, PDF (2/9 Pages) NXP Semiconductors – CMOS single-chip 8-bit microcontrollers

MAX186 Evaluation System/Evaluation Kit
The MAX233 also generates the output voltages neces-
sary to drive RS-232 lines.
Port 0 (pins 32-39) of the 80C32 multiplexes the lower
eight bits of memory address and the eight bits of
read/write data. The lower eight bits of address data
are latched during each I/O cycle by the 74HCT573
octal latch. The latch is controlled by the address latch
enable (ALE) signal of the 80C32. Port 2 (pins 21-28) of
the 80C32 supplies the upper eight bits of address
information.
The port 3 pins (10-17) provide several unrelated func-
tions. Pins 10 and 11 are used as the receive data
(RxD) and transmit data (TxD) pins of the RS-232 link.
Pins 16 and 17 act as the write (WR) and read (RD) con-
trol signals for the data I/O cycles. Four other pins are
configured as interrupt and timer controls, but are not
used on this board.
Memory
The board has a 27C64 EPROM containing code for ini-
tializing the 80C32 and downloading additional pro-
gram code to the 62256 RAM. After a reset, the EPROM
resident code initializes the 80C32, determines the
address range of the RAM, sets the RS-232 baud rate
to 1200, and waits for communications from the PC.
Receiving any character will prompt the program to
send an initial banner that includes the program name,
revision level, and boundaries of the on-board RAM.
The 62256 CMOS (32kbyte) static RAM is used to hold
program code for the various Maxim EV kits that use
the 80C32 module as the controller. Programs are
transferred from disk to the RAM using software run-
ning on a personal computer, such as MAXLOAD or
other programs provided with Maxim EV kits. Programs
written to execute from this RAM start at 4000 (HEX)
and are typically less than 4kbytes long. The remaining
RAM is available for data storage.
Address Ranges
Logic on the module board generates various enable
signals for different address ranges. The ROM and
RAM enable signals are fed directly to the respective
chips. Several additional signals (CS0-CS3) are avail-
able on the data connector to be used by Maxim EV
kits. Table 1 outlines the address range for each of the
elements found on the 80C32 module.
Table 1. Address Ranges in Hexadecimal
ADDRESS RANGE (HEX)
ENABLE SIGNAL
0000
4000
C000
D000
E000
F000
3FFF
BFFF
CFFF
DFFF
EFFF
FFFF
ROM
RAM
CS0
CS1
CS2
CS3
Data I/O Connector
A 40-pin connector mounted on the edge of the printed
circuit board provides connection between the µC
module and other Maxim EV kits. Both power and digi-
tal signals are transferred via the connector. To join the
module board with an EV kit, carefully align and insert
the pins on the connector with the mating 40-pin female
connector of the kit. The pin functions are listed in
Table 2.
Table 2. I/O Connector Pin Functions
PIN
FUNCTION
DESCRIPTION
1-4
5, 6
7, 8
9
10
11
12
13
14
15-18
19-26
27-34
35-40
Ground
Pre-regulator input
Regulated +5V
RD
WR
CS0
CS1
CS2
CS3
ADDR0-ADDR3
DB0-DB7
P1.0-P1.7
Reserved
Read strobe
Write strobe
Address C000-CFFF
Address D000-DFFF
Address E000-EFFF
Address F000-FFFF
Lowest 4 bits of address
8-bit data bus
8 bits of port 1
______________________________________________________________________________________ 13